Asymmetric synthesis of novel ferrocenyl ligands with planar and central chirality and their application to Pd-catalyzed allylic substitutions

FULL PAPER

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central

Chirality and Their Application to Pd-Catalyzed Allylic Substitutions

[a]

´

Dieter Enders,* Rene Peters, Rene Lochtman, Gerhard Raabe, Jan Runsink, and

Jan W. Bats^[b]

Dedicated to Professor Richard Neidlein on the occasion of his 70th birthday

Keywords: Asymmetric synthesis / Hydrazones / Ferrocenyl ligands / Asymmetric catalysis / Allylic substitution

An efficient and flexible asymmetric synthesis of planar

chiral ferrocenyl ligands bearing a stereogenic centre at the

oselective allylic substitutions. By employing a P,S ligand, the

alkylation of the standard test system (±)-1,3-diphenyl-2-pro-

β-position to the metallocene backbone is described. A vari- penyl acetate using dimethyl malonate/BSA as the nucleoph-

ety of donor groups can be independently introduced as elec-

trophiles, thus allowing electronic and steric fine-tuning of

the ligands, which were investigated in Pd-catalyzed enanti-

ile proceeded in a quantitative yield with an ee of 97%,

which is the best value reported so far in this reaction for a

PʜS ligand.

Introduction

those compounds could not previously be synthesized

stereoselectively. In 1981 Kumada et al. described the only

synthesis of the homologous compound B (E¹ϭ NMe₂,

E²ϭ PPh₂) of diphenylphosphanylferrocenylethylamine

(PPFA), which required separation of racemates and

diastereoisomers.^[6]

The application of ferrocenyl ligands possessing planar

chirality in asymmetric catalysis has recently received con-

siderable interest.^[1]In most cases, the employed ferrocene

ligands are of type A, which is accessible from enantiomer-

ically pure Ugi amine (Nu ϭ NMe₂, E ϭ H) by diastereose-

lective ortho-metallation, trapping of the resulting car-

banion with a suitable electrophile and subsequent nucleo-

philic displacement of the dimethylamino functionality with

retention of configuration via an intermediately formed car-

bocation.^[1,2]In the meantime, several efficient stereoselec-

tive syntheses of the enantiomerically pure Ugi amine and

related compounds have been developed.^[3]Planar chiral

ferrocenes A, which in addition possess a stereogenic centre

Results and Discussion

Our SAMP/RAMP-hydrazone method [SAMP and

in the α-position, have shown efficiency as ligands for cata- RAMP ϭ (S)- and (R)-1-amino-2-methoxymethylpyrroli-

lytic asymmetric synthesis both in research and industrial din] seemed to be appropriate for the asymmetric synthesis

processes.^[4]We would therefore like to report a straightfor- of planar chiral ligands B bearing a stereogenic centre at

ward asymmetric synthesis of planar chiral ferrocenyl li- the β-position of the ferrocene backbone, since not only

gands of type B bearing a stereogenic centre in the β-posi- would the highly diastereoselective alkylation α to the hy-

tion of the side chain. Parts of this work were recently pub- drazone functional group be possible,^[7]but also the intro-

lished as preliminary communications.^[5]The initial aim for duction of various heteroatom functionalities with similarly

synthesizing ligands of type B was to investigate the effect high asymmetric inductions. In the context of ligand syn-

that changing the position of the chiral centre from the α- thesis, this would necessarily require the use of phos-

to the β-position would have on the levels of asymmetric phorus,^[8]sulfur,^[9]and nitrogen electrophiles.^[10]In addi-

induction for catalytic processes. The field of such planar tion, since we have recently demonstrated that benzoylferro-

chiral ferrocenes had been little studied before, because cene-SAMP-hydrazones may be easily functionalized at the

ortho-position with high diastereoselectivity,^[11]it was de-

cided to combine both synthetic strategies. As starting mat-

erial, we used ferrocenyl ketones 1 with α-acidic protons,

which may be accessed simply by FriedelϪCrafts acyl-

ation.^[12]Since the ketones were only weakly electrophilic,

owing to the electron-donating character of the ferrocenyl

system, quantitative conversion into mixtures of (E/Z)-

[a]

Institut für Organische Chemie, Rheinisch-Westfälische

Technische Hochschule,

Professor-Pirlet-Straße 1, 52074 Aachen, Germany

Fax: (internat.) ϩ 49-241/8888-127

E-mail: enders@rwth-aachen.de

[b]

Institut für Organische Chemie der Universität Frankfurt,

Marie-Curie-Straße 11, 60439 Frankfurt am Main, Germany

Eur. J. Org. Chem. 2000, 3399Ϫ3426

WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

1434Ϫ193X/00/1020Ϫ3399 $ 17.50ϩ.50/0

3399

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

SAMP-hydrazones 2 was achieved by using AlMe₃activa- 7 formed yellow-orange precipitates. However, with LiClO₄,

tion (Table 1, Scheme 1).^[11,13]

orange-brown homogeneous solutions were obtained. It is

well-known that LiClO₄leads to deaggregation of organoli-

thium species, and this explains the differing solubilities and

selectivities observed.^[14]By trapping the metallated species

at Ϫ100 °C with the required electrophile, the desired α-

functionalized hydrazones 3 were available in good yields

and with (E/Z) ratios up to Ն 100:1 (Table 2). The (E) and

(Z) isomers were diastereomerically pure, with the excep-

tion of 3b where R is a phenyl group, presumably owing to

epimerization caused by activation by the aromatic part.

The residue R has a considerable influence on the (E/Z)

selectivity. Whereas for R ϭ Me, Et, Ph (E)-hydrazones are

formed preferentially, the branched iPr group yields (Z)-hy-

drazones.

Table 1. Synthesis of ferrocenyl ketone-SAMP-hydrazones 2

2

R

Yield [%]

(E)/(Z)

a

b

c

Me

Et

iPr

Ph

95

2.8:1

3.1:1

2.2:1

4.3:1

100

84

d

77

Table 2. Regio- and diastereoselective functionalization of the

side chain

3

R

E¹

(E)/(Z)

de [%]

Yield [%]

a

b

c

d

e

f

Et

Me

54:1

Ն 96

48

93

95

91

97

95

93

92

97

96

88

95

82

99

Ph

Me

Et

Me

Ն 100:1

20:1

Ph₂PBH₃

SMe

Ն 96

44:1

Me

Et

Me

Et

Me

iPr

Et

12:1

SMe

28:1

g

h

i

SiPr

50:1

SiPr

9:1

iPr₂PBH₃

STol

9:1

j

Յ 1:100

Յ 1:50

7:1

k

l

Me

SMe

m

STol

The different configurations of the new stereogenic centre

α to the hydrazone moiety can be explained as shown in

Scheme 2. Both azaenolates 7 will adopt the (E_CC) config-

uration as is usually the case for lithiated SAMP-hy-

drazones. The electrophilic attack occurs from the sterically

less hindered exo side. The opposite configurations are the

result of different conformations (rotation around the

CpϪC bond). This assumption is based on the fact that

ortho-lithiated (E)- and (Z)-ferrocenyl ketone SAMP-hy-

drazones bear different configurations with respect to

planar chirality, showing that they also react in different

conformations.^[15]

Scheme 1. Asymmetric synthesis of target ligands 6: a) 2.0 equiv.

SAMP/AlMe₃, toluene, T; b) 1) 1.2 equiv. LDA, 3.3 equiv. LiClO₄,

Et₂O, roomp. temp., 2) E¹X, Ϫ100 °C; c) 1) x equiv. tBuLi, y equiv.

LiClO₄, THF, Ϫ70 °C, 2) E²X; d) catecholborane, CH₂Cl₂/Et₂O,

Ϫ40 °C to room temp.; e) TFA/NaBH₄, CH₂Cl₂, 0 °C or 1) 2.5

equiv. HBF₄, 0 °C, CH₂Cl₂, 2) 5.0 equiv. HBEt₃Li

The regioselective metallation of the side chain was pos-

sible with lithium diisopropylamide (LDA). After trapping

the azaenolate of 2 with electrophiles, we first obtained (E/

Z)-hydrazone mixtures 3 (6.7:1 to 1:3.3), in which the new

stereogenic centre in each of the (E) and (Z) isomers unex-

pectedly was found to bear the opposite configuration. It

was therefore necessary to find conditions which would

yield only one geometric hydrazone isomer. Accordingly, we

examined the influence of base, solvent, co-solvent, addit-

ives, reaction time, reaction temperature, transition metal

salts for transmetallation of the lithio azaenolates, and of

SAMP-auxiliary derivatives on the (E/Z) ratio. Finally, we

Scheme 2

For our studies we chose alkyl, phosphorus, and sulfur

discovered that upon metallation in diethyl ether at room electrophiles. The BH₃-protected phosphorus derivatives

temperature, the addition of LiClO₄resulted in the desired were found to undergo (E/Z) isomerization in diethyl ether

high (E/Z) ratios (Scheme 1). Without LiClO₄, azaenolates or benzene at room temperature. In order to avoid this pro-

3400

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

cess, the completed reaction had to be worked up rapidly Table 3. Regio- and diastereoselective functionalization of the or-

tho-Cp position

and at low temperatures (0 °C). Purification by column

chromatography was also avoided for this reason; filtration

4

R

E¹

E²

x

y

Yield [%] de [%]

through silica gel and subsequent crystallization from hex-

ane at Ϫ26 °C yielded the analytically pure compounds.

The unprotected phosphanes were found to isomerize much

faster than the BH₃-protected phosphanes. In addition,

they were observed to undergo rapid oxidation. As a result,

the use of the protecting group was preferred, since the pro-

tected compounds turned out to be highly robust. The sul-

fur derivatives did not show any tendency to undergo iso-

merization.

a

b

c

d

e

f

Et

Ph₂PBH₃Me

Ph₂PBH₃SMe

4.0 6.0 55

3.0 6.0 65

2.5 6.0 94

3.0 6.0 76

1.3 3.0 83

96

Ն 90

Ն 96

96

Me Ph₂PBH₃SMe

Me iPr₂PBH₃STol

Et

SMe

Me

Me SMe

Ph₂PBH₃1.2 3.0 86

Ph₂PBH₃1.1 3.0 77

iPr₂PBH₃1.2 3.0 93

Ph₂PBH₃1.2 3.0 73

g

h

i

Et

SMe

Ն 96

Ն 90

Ն 96

Ն 90

Ն 96

Ն 90

Ն 96

Me SiPr

j

Et

SMe

SiPr

SMe

STol

SePh

SMe

I

2.0 4.0 98

1.1 3.0 89

1.2 3.0 98

1.3 3.0 28

2.5 5.0 44

k

l

The regio- and diastereoselective metallation of the Cp

ring ortho to the directing hydrazone moiety of 3 was

achieved through optimization of the metallation condi-

tions. Again the use of lithium perchlorate turned out to be

advantageous. In the presence of anion-stabilizing RS^[16]

and R₂PBH₃substituents,^[17]the side chain is deprotonated

in the position α to the hydrazone moiety in the absence

of LiClO₄, thus destroying the new stereogenic centre and

causing (E/Z) isomerization. However, in the presence of

LiClO₄in combination with tBuLi/THF at Ϫ70 °C,

metallation of the side chain was completely avoided. In

this step, the (E) isomers were further enriched, since the

(E)-configured hydrazones 3 underwent ortho-metallation

more readily than the (Z)-configured isomers. The low

tendency of (Z)-hydrazones to undergo ortho-metallation

also explains the low yield of ortho-functionalization of hy-

drazone (Z)-3j (Table 3). In order to achieve high yields

with the R₂PBH₃-substituted hydrazones 3, an excess of

base was necessary (2.5 to 3 equiv.). However, this was not

found to have any negative influence on the regio- or dias-

tereoselectivity. A double metallation was not observed in

any case. It is noteworthy that the planar chiral products 4

do not show any tendency to undergo (E/Z) isomerization

at room temperature. The ortho-metallation of the thiolated

hydrazones 3 proceeded using only 1 equiv. tBuLi. After

the optimum reaction conditions had been found, we used

various phosphorus, sulfur and selenium electrophiles for

ligand synthesis (Table 3). The new method allows for the

successive, highly diastereoselective introduction of two dif-

ferent electrophiles. Unfortunately we have not yet been

able to introduce two diphenylphosphanyl groups in an ac-

ceptable yield. This is probably due to steric crowding.

Subsequently, the planar chiral (E)-configured SAMP-

hydrazones 4 could be transformed into the hydrazines 5 by

reduction with catecholborane in diethyl ether/dichlorome-

m

n

iPr STol

Me Ph₂PBH₃

gen atom, thus enhancing the electrophilicity of the CϭN

double bond and the nucleophilicity of the hydride

(Scheme 3). (Z)-Hydrazones 4 did not undergo reduction.

Compounds bearing a BH₃-protected phosphanyl group in

the side chain had to be deprotected with N,N,NЈ,NЈ-tetra-

methylethylenediamine (TMEDA) to achieve acceptable

yields. As the catecholborane reduction proceeds with high

diastereoselectivity, the protocol described allows for the

stereocontrolled generation of two contiguous stereogenic

centres at the α- and β-positions in addition to the planar

chirality.

Table 4. Diastereoselective reduction of planar chiral hydrazones 4

5

R

E¹

E²

Yield [%]

de [%]

a

b

c

d

e

f

Et

SMe

Me

93

39

82

55

43

75

88

68

58

40

Ն 96%

87

Ն 96%

Me

Et

SMe

Ph₂PBH₃

iPr₂PBH₃

Ph₂PBH₃

SMe

Et

SMe

Me

Et

SiPr

SMe

g

h

i

Et

SiPr

STol

Et

SiPr

SePh

Me

Et

Ph₂PBH₃

SMe

j

SMe

thane (1:1 to 2:1) (Table 4). With hydride reducing agents Scheme 3

such as LiAlH₄, HBEt₃Li, LiBH₄, NaBH₄etc., no reaction

was observed under various reaction conditions owing to

The X-ray structure analysis of 5e (Figure 1) proves the

the electron-donating character of the ferrocene moiety, absolute configuration shown in Scheme 1. The stereochem-

which significantly decreases the electrophilicity of the Cϭ istry can be explained by the preferential exo attack of the

N double bond. Under acidic reaction conditions, solutions reducing agent. Since uniform reaction pathways may be

of ferrocenyl ketone SAMP-hydrazones show a dark red- assumed, all compounds 5 were assigned as bearing the

brown or purple colour owing to the formation of a me- same absolute configuration. The configuration was con-

somerically stabilized cation. The same colour is observed firmed by NOE measurements of hydrazine 5b (¹¹B decoup-

with the addition of catecholborane, demonstrating that the ling). The NMR studies also reveal the same conformation

Lewis-acidic boron atom is coordinated by the imino nitro- for molecules in solution and in crystalline form. In the

Eur. J. Org. Chem. 2000, 3399Ϫ3426

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D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

Scheme 4

(ee Ն 96% to Ն 99%) and with high diastereoselectivity

(de ϭ 94Ϫ97%, Table 5).

Figure 1. Crystal structure of hydrazine 5e

Cleavage of the BH₃protecting group was accomplished

by the use of TMEDA. Phosphanyl groups bearing three

aromatic substituents could be deprotected at room temper-

ature, whereas deprotection of the alkyl-substituted phos-

phanes required higher temperatures (Table 6).

Protonation of hydrazines 5b,c with HBF₄· OEt₂fol-

lowed by the addition of lithiated benzylamine furnished

the deprotected phosphanes 6j؊n in a single step from hy-

drazines 5 (Scheme 4). Lithiated benzylamine removed the

BH₃protecting group yielding an anionic hydroborate re-

agent which traps carbocation 8.

As could be shown for one example, the new methodo-

logy is also applicable in the generation of C₂-symmetric

ligands possessing only central chirality (Scheme 5). Bis(hy-

drazone) 10, easily accessible from diketone 9 in high yield,

was transformed into a dianion with LDA. Trapping with

(MeS)₂yielded bis(thioether) 11. Reduction with catechol-

borane in the absence of an ortho substituent furnished bi-

s(hydrazine) 12, without stereoselectivity, in moderate yield.

Cleavage of the auxiliary provided SʜS ligand 13.

In order to compare the efficiency in asymmetric catalysis

of ligand type B with type A, we chose the Pd-catalyzed

allylic substitution, since this reaction is one of the best

understood catalytic asymmetric transformations.^[19]Dur-

ing the catalytic course, a meso-type π-allyl species 14 is

formed, if both residues R are identical (Scheme 6). The

enantioselectivity of this reaction is determined by the re-

gioselectivity of the nucleophilic attack. This goal is diffi-

cult to achieve when only taking the steric bulk of the li-

gand into account, since the new CϪNu bond is formed

outside the coordination sphere of the metal centre. There-

fore regioselective nucleophilic attack is often achieved by

electronic means, employing bidentate hybrid ligands pos-

side chain, H_αand H_βadopt a rigid gauche conformation

(³J_HHϭ 1.6 Hz).

In order to remove the auxiliary, hydrazines 5 were pro-

tonated with either HBF₄or trifluoroacetic acid. The

method of choice for BH₃-protected PʜS ligands 6 was pro-

tonation with HBF₄and trapping the resulting carbocation

with Superhydride (HBEt₃Li). The SʜS and the SʜSe li-

gands 6 were obtained by the combination TFA/NaBH₄.^[18]

The cations of the latter systems turned out to be remark-

ably unstable. Therefore, the presence of the hydride reagent

was necessary during the acidic reaction conditions. In con-

trast, the cations of the PʜS systems were found to be so

stable that they could only be trapped using extremely nu-

cleophilic reagents such as HBEt₃Li. The title compounds

6 were synthesized in virtually enantiomerically pure form

Table 5. Auxiliary cleavage

6 R E¹

E²

Yield [%] de [%] ee [%] [α]_D(CHCl₃)

25

a Me Ph₂PBH₃SMe

b Et Ph₂PBH₃SMe

70

51

94

97

95

97

95

94

97

Ն 99^[a]ϩ15.6

Ն 99^[a]Ϫ22.4

Ն 96^[b]Ϫ149.4

Ն 96^[b]Ϫ192.4

Ն 96^[b]ϩ100.0

Ն 96^[c]Ϫ86.9

Ն 99^[b]Ϫ181.3

Ն 99^[a]Ϫ5.9

c Me SMe

d Et SMe

e Et SMe

f Me SiPr

g Et SMe

h Et SiPr

i Et SiPr

Ph₂PBH₃95

Ph₂PBH₃90

iPr₂PBH₃88

Ph₂PBH₃81

SMe

STol

SePh

95

84

70

Ն 96 Ն 99^[d]Ϫ8.0

[a]

Determined by HPLC on a chiral stationary phase (Chiracel

OD-H). Ϫ ^[b]Determined by ¹H NMR using (Ϫ)-(R)-1-(9-anthryl)-

[c]

2,2,2-trifluoroethanol as a chiral cosolvent. Ϫ

Determined by

[d]

GC on a chiral stationary phase (Chirasil dex 25 m). Ϫ

Deter-

mined by HPLC on a chiral stationary phase (Chiracel OD-2).

Table 6. BH₃deprotection

E¹

E²

TMEDA

Solvent

T [°C]

Yield [%]

de [%]

[α]_D(CHCl₃)

25

6

R

j

Et

SMe

SiPr

PPh₂

PiPr₂

PPh₂

SMe

5.0 eq

10.0 eq

5.0 eq

10.0 eq

Et₂O

20

90

20

90

88

51

95

91

59

Ն 96

97

Ն 96

Ϫ263.1

Ϫ240.9

Ϫ83.4

Ϫ186.0

ϩ67.9

k

l

Me

Et

Et₂O

toluene

toluene/Et₂O

toluene

m

n

Me

3402

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

sessing two electronically different donor atoms. One is a

σ-donor (like N or S) and one is a σ-donorϪπ-acceptor planar coordination sphere around the central metal ion.

In general, (π-allyl)Pd^IIcomplexes 14 adopt a square-

(e.g. P).

Two bonds in a trans position compete for one metal d-

orbital for a π-back bond. The stronger the π-acceptor abil-

ity of the ligand is, the more electronic density is removed

from the metal d-orbital. That means the electronic density

of the terminal allylic carbon atom is strongly reduced by

a π-acceptor in a trans position, thus enhancing its electro-

philicity. This strategy has previously been successfully ap-

plied by the use of PʜNϪ,^[20]NʜSϪ^[21]and PʜSϪPd che-

lates.^[22]Another significant factor is the configuration of

the allylic fragment. (W)- and (M)-14 yield differently con-

figured products 15 determining one of the ligands tasks:

the preferential formation of one allylic isomer.

Ferrocenyl ligands of type B were investigated in the al-

kylation of the standard test system (Ϯ)-(E)-1,3-diphenyl-

2-propenyl acetate (16) employing dimethyl malonate/BSA

as nucleophile (Scheme 7, Table 7). All these ligands have

at least one sulfur donor group (E¹or E²). The second

donor atom may be P, Se, or another S. SʜS and SʜSe

ligands 6h and 6i displayed low reactivity and selectivity.

Even after 100 h in dichloromethane at room temperature

the reaction was not complete. The low reactivity can be

explained by the high electron density of the central metal

ion owing to the weak π-acceptor abilities of the S and Se

groups.^[23]The low ee values of 20 and 44%, respectively,

result from only minimum electronic differentiation. By em-

ploying PʜS ligands, we found a completely different situ-

ation. The (π-allyl)Pd complex is strongly activated by the

P group as π-acceptor. In combination with the thioether

Scheme 5. Asymmetric synthesis of SʜS ligand 13: a) 4.0 equiv.

SAMP/AlMe₃, toluene, T; b) 1) 2.5 equiv. LDA, 9.0 equiv. LiClO₄,

Et₂O, roomp. temp., 2) 3.0 equiv. (MeS)₂, Ϫ100 °C; c) 8.0 equiv.

catecholborane, CH₂Cl₂/Et₂O, Ϫ50 °C to room temp.; d) TFA/

NaBH₄, CH₂Cl₂, 0 °C

Scheme 7. Pd-catalyzed allylic alkylation; reaction conditions: x

mol-% [Pd(η³-C₃H₅)Cl]₂, y mol-% 6, 1.0 mol-% KOAc, 3.0 equiv.

dimethyl malonate/BSA, CH₂Cl₂, Ϫ20 °C or room temp.

Scheme 6

Table 7. Application of the novel ligands 6 in the Pd-catalyzed allylic alkylation (16 Ǟ 17)

6

E¹

E²

R

T [°C]

x [mol-%]

y [mol-%]

t [h]

Yield [%]

ee [%]^[a]

Config.

h

i

SiPr

SMe

SiPr

PPh₂

STol

SePh

PPh₂

PiPr₂

PPh₂

SMe

Et

20

2.5

1.0

2.5

5.5

2.2

5.5

100

0.16

24

84

65

99

98

99

20

44

90

97

91

70

80

0

(R)

Ϫ

Et

20

k

j

Et

20

Et

Ϫ20

20

Me

Et

0.16

1

l

m

n

20

Me

20

1

20

[a]

1

Determined by H NMR with chiral shift reagent Eu(tfc)₃.

Eur. J. Org. Chem. 2000, 3399Ϫ3426

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D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

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unit, we have a hybrid system that allows for electronic con-

trol of the nucleophilic attack on the allylic system. Using

ligands 6j and 6k, the reaction proceeded quantitatively

within 10 min at room temperature in CH₂Cl₂(yield ϭ 99

and 98%, respectively) affording product (R)-17 with an en-

antiomeric excess of 90 and 91%, respectively. By changing

the PPh₂group of 6j to the PiPr₂group (ligand 6l), the ee

was lowered from 90 to 70%, probably partly owing to the

PiPr₂moiety being a weaker π-acceptor leading to a de-

crease in regioselectivity of the nucleophilic attack. The ob-

served results indicate that the steric control also has to be

fine-tuned. Since nucleophilic attack is preferred cis to the

S donor group, this should be even more favourable with

smaller thioether units. Changing the SMe group of 6k to

the SiPr group (ligand 6m) decreases the ee from 91 to 80%.

The steric influence is demonstrated with PʜS ligand 6n,

which yields the racemic product, since the thioether group

is connected to the bulky ferrocenyl core.

Scheme 8. Pd-catalyzed allylic alkylation; reaction conditions: 1.0

mol-% [Pd(η³-C₃H₅)Cl]₂, 2.2 mol-% 6j, 1.0 mol-% KOAc, 2.5 equiv.

BnNH₂, CH₂Cl₂, Ϫ20 °C

substituents on allylic ligands are named according to their

configuration relative to the central CϪH bond) by ¹H

NMR NOE experiments (Figure 2). The terminal allylic

proton trans to the thioether moiety shows a very intense

interaction with the ortho protons of the endo-phenyl res-

idue of the PPh₂groups. The ortho protons of the phenyl

ring on the allylic terminus trans to P interact significantly

with the SCH₃group and SCH. In combination with the

intraallylic interactions, the exo-syn-syn configuration can

unambiguously be assigned.

Owing to the high reactivity of the (allyl)Pd complexes

with ligands 6j and 6k, it was possible to run the reaction

at Ϫ20 °C in order to enhance the stereoselectivity. Sub-

sequently, we concentrated on ligand 6j, despite the fact

that 6k gave slightly better results, since the former can be

obtained in higher yields and it is far less air-sensitive. The

product could be isolated in quantitative yield and with an

ee value of 97% by a simultaneous decrease in the amount

of catalyst from x ϭ 2.5 to x ϭ 1.0 mol-% (y ϭ 2.2 mol-%

6j). The high selectivities are noteworthy, since ligands 18

bearing the stereogenic centre in the α-position yield the

product with an ee of only 34% (R ϭ ethyl) or 67% (R ϭ

cyclohexyl). By changing the alkyl group of the sulfur

donor atom to a chiral sugar moiety Pregosin et al. were

able to improve the ee to 88%.^[22c]To the best of our know-

ledge, an enantiomeric excess of 97% is the best value for

this reaction for a PʜS ligand reported to date. PʜS li-

gands have the advantage of higher reactivity and therefor

much shorter reaction times than NʜS ligands.

Figure 2. NOE connectivities for Pd complex 20

The ¹³C NMR chemical shifts for the allyl terminus trans

to the phosphorus atom (δ ϭ 102.5) and trans to sulfur

atom (δ ϭ 78.2) indicate that the carbon atom trans to the

phosphorus atom should be much more electrophilic, thus

allowing for regiocontrol of the nucleophilic attack

(ground-state argument). Based on the plausible assump-

tion that (R)-17 and (S)-19 result from preferential attack

on this major exo-syn-syn isomer, then the nucleophilic at-

tack proceeds as expected trans to the phosphorous atom.

More detailed information about the way in which our

catalyst 20 works was obtained from the solid-state struc-

ture that also reveals the exo-syn-syn geometry with a dis-

torted square-planar coordination around the palladium

centre (Figure 3). The 1,3-diphenylallyl ligand is rotated in

a clockwise manner along the PdϪallyl axis as seen from

A temperature effect similar to the alkylation noted be-

fore was found for the amination reaction using benzylam-

ine as nucleophile (Scheme 8). Reducing the reaction tem-

perature from ϩ20 °C to Ϫ20 °C increased the ee of 19

from 84 to 94% [(S) configuration]. However, this higher

selectivity was accompanied by a decrease in yield from 93

to 50%.

To be able to explain the high efficiency of our catalyst, the allyl ligand towards the Pd atom so that the terminal

we had to examine its configuration and structure. For allyl carbon atom trans to the phosphorus atom (C-7) is

˚

CDCl₃solutions of complex 20, we observed four isomers found to be 0.447 A below the PϪPdϪS coordination

in the ratio 86:9:3:2 with ³¹P NMR chemical shifts of δ ϭ plane. In contrast, C(8) and C(9) are 0.450 A and 0.136 A,

15.2, 14.9, 17.8, and 21.1, respectively. The configuration of respectively, above this plane, indicating that the π-back

the major isomer was unambiguously determined to be exo- bond to C(7) should be much less intense than to C(9) for

syn-syn (exo refers to the relative orientation of the central orbital symmetry reasons. This means that C(7) should be

allylic CϪH vector pointing away from the ferrocenyl core; much more electrophilic (ground-state argument). As ex-

˚

3404

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

pected, the PdϪC bond lengths are significantly different, plex 20 the thioether unit is in the sterically unfavourable

with the carbon atom trans to the phosphorus atom having endo position, whereas for 20 the SMe group is in the

˚

the longer distance [PdϪC(7) ϭ 2.274(5) A] than the one sterically favourable exo position. The bite angle for 21 is

˚

trans to the sulfur atom [PdϪC(9) ϭ 2.176(4) A] indicating 96.5°. For 20 we found 91.2°, contradicting the theory that

again the higher trans influence of the phosphanyl moiety. larger bite angles lead to higher inductions for allylic substi-

The plane of the allyl fragment is tilted 22.8° from the per- tutions with comparable ligands, since the chirality in-

pendicular to the PϪPdϪS coordination plane. Similar formation of the ligand should be closer to the allylic sys-

values have been observed for related compounds.

tem.^[19a]

Figure 3. Crystal structure of Pd complex 20 (without anion and

solvent) with 50% probability displacement ellipsoids; selected

bond lengths are: PdϪS ϭ 2.400(1), PdϪP1 ϭ 2.326(1), PdϪC7 ϭ

2.274(5), PdϪC8 ϭ 2.188(4), PdϪC9 ϭ 2.176(4), C7ϪC8 ϭ

Figure 4. Crystal structure of the related Pd complex 21

˚

1.384(6) and C8ϪC9 ϭ 1.404(6) A

Figure 5 shows a schematic superposition of the struc-

tures of complexes 20 (smooth line) and 21 (dotted line).

With the allylic carbon terminus trans to the sulfur atom

being fixed, the ferrocenyl moieties are rotated nearly per-

pendicular to each other, thus resulting in a different ar-

The preferred exo-syn-syn configuration is stabilized by

two intramolecular CϪH···π-arene interactions between

one allylic phenyl group with the exo-phenyl ring of the

˚

PPh₂group (H···π: 2.73 A; CϪHϪπ: 136°) and of the other

˚

allylic phenyl group with an SCH₃proton (H···π: 2.77 A;

CϪHϪπ: 131°). An additional intramolecular CϪH···π in-

teraction is found between a ferrocenyl CϪH bond of the

unsubstituted Cp ring and the endo-phenyl ring of the PPh₂

˚

group with a C···π distance of 2.50 A and a CϪHϪπ angle

of 150°.

Figure 4 shows the solid-state structure of Pd complex 21

possessing a chiral ferrocenyl ligand 18.^[22c]This complex

was thus far the most successful catalyst bearing a PʜS

ligand in the above-mentioned test reaction for allylic sub-

stitution. The structure is remarkable for the following

reason: The 1,3-diphenylallylic system is rotated in an ex-

treme fashion. The allylic carbon terminus trans to phos-

˚

phorus atom is found to be 0.85 A below the coordination

plane PϪPdϪS. This is the largest distortion known for a

(π-allyl)Pd complex. The other two allylic carbon atoms

now lie almost in the PϪPdϪS coordination plane, thus

preparing for a transition state forming a Pd⁰olefin struc-

ture. Consequently, to generate an (olefin)Pd⁰complex by

nucleophilic attack, the reorientation of the ligand is negli-

gible, thus favouring nucleophilic attack trans to the phos-

Figure 5. Schematic superposition of 20 (smooth line) and 21 (dot-

phorus atom (least-motion principle). Compared to com- ted line)

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3405

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

4.09 (t, ^3/4J ϭ 2.0 Hz, 2 H, m-C₅H₄R), 4.65 (t, ^3/4J ϭ 2.0 Hz, 2 H,

o-C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 8.6 (CH₃), 32.7

(CH₂), 69.5, 71.9 (C₅H₄R), 69.8 (C₅H₅), 79.9 (i-C₅H₄R), 202.6 (Cϭ

O). Ϫ EI-MS; m/z: 242.0 (100) [M^ϩ], 212.9 (59) [M^ϩϪ CH₂CH₃],

184.9 (20) [Fc^ϩ], 129.0 (80) [C₁₀H₉^ϩ], 120.8 (41) [CpFe^ϩ], 55.9 (34)

[Fe^ϩ]. Ϫ C₁₃H₁₄FeO (242.1): C 64.49, H 5.83; found C 64.40, H

6.00.

rangement of the Ph groups of the PPh₂group and thus

creating a totally different chiral environment. Now we

should be able to explain the efficiency of our catalyst in

the following way: a) The ligand allows for the regioselec-

tive control of the nucleophilic attack by electronic differen-

tiation of the allylic carbon termini. b) The exo-syn-syn

configuration is strongly favoured by intramolecular

CϪH···π interactions.

1-Ferrocenyl-1-butanone (1b): According to GP1, a solution of

ferrocene (10.00 g, 53.8 mmol) in CH₂Cl₂(40 mL) was treated with

a solution of AlCl₃(7.60 g, 1.06 equiv.) and butyryl chloride

(5.78 g, 1.01 equiv.) in CH₂Cl₂(30 mL). After stirring for 48 h at

room temperature, the reaction mixture was worked up and the

product purified by filtration through silica gel (hexane/diethyl

ether ϭ 2:1). Ϫ Yield: 11.30 g (82%, dark red crystals). Ϫ R_fϭ

0.44 (petroleum ether ether/diethyl ether ϭ 2:1). Ϫ M.p.: 36 °C. Ϫ

IR (KBr): ν˜ ϭ 3120 cm^Ϫ1, 3085, 2954, 2930, 2893, 2870, 2254,

1786, 1668, 1456, 1408, 1378, 1348, 1301, 1237, 1122, 1104, 1061,

1027, 1000, 900, 883, 836, 817, 700, 745, 646, 595, 534, 500, 481,

Conclusion

In summary, we have opened up an efficient and flexible

approach to planar chiral ferrocenyl ligands bearing a ste-

reogenic centre in the β-position of the side chain. We found

that these ligands may be superior to α-functionalized

ferrocenes in certain catalytic reactions, as demonstrated for

the Pd-catalyzed allylic substitution.

1

3

464. Ϫ H NMR (300 MHz, CDCl₃): δ ϭ 1.01 (t, J ϭ 7.4 Hz, 3

H, CH₃), 1.74 (sext, ³J ϭ 7.4 Hz, 2 H, CH₂CH₃), 2.68 (t, ³J ϭ

7.2 Hz, 2 H, COCH₂), 4.20 (s, 5 H, C₅H₅), 4.49 (t, ^3/4J ϭ 2.0 Hz,

2 H, m-C₅H₄R), 4.78 (t, ^3/4J ϭ 2.0 Hz, 2 H, o-C₅H₄R). Ϫ ¹³C NMR

(75 MHz, CDCl₃): δ ϭ 14.1 (CH₃), 18.0 (CH₂CH₃), 41.7 (COCH₂),

69.3, 72.1 (C₅H₄R), 69.7 (C₅H₅), 79.3 (i-C₅H₄R), 204.5 (CϭO). Ϫ

EI-MS; m/z: 256.1 (100) [M^ϩ], 228.0 (11) [M^ϩϪ CO], 213.0 (57)

[FcCO^ϩ], 185.0 (46) [Fc^ϩ], 129.0 (30) [Fc^ϩϪ Fe], 120.9 (21)

[CpFe^ϩ], 56.0 (21) [Fe^ϩ]. Ϫ C₁₄H₁₆FeO (256.1): calcd. C 65.65, H

6.30; found C 65.99, H 6.28.

Experimental Section

General Remarks: All solvents were dried and distilled prior to use.

Ϫ Column chromatography: Merck silica gel 60, 0.040Ϫ0.063 mm

(230Ϫ400 mesh) (flash). Ϫ Optical rotation values: PerkinϪElmer

P 241, solvent UVASOL quality. Ϫ Melting points (uncorrected):

Büchi 510. Ϫ IR: PerkinϪElmer FT 1750. Ϫ NMR: Varian VXR

300 and Gemini 300 (300 and 75 MHz for ¹H and ¹³C, respect-

ively), Varian Inova 400 (400, 100 and 162 MHz for H, ¹³C, and

1

1-Ferrocenyl-3-methyl-1-butanone (1c): According to GP1, a solu-

tion of ferrocene (10.00 g, 53.8 mmol) in CH₂Cl₂(40 mL) was

treated with a solution of AlCl₃(7.60 g, 1.06 equiv.) and isovaleryl

chloride (6.55 g, 1.01 equiv.) in CH₂Cl₂(30 mL). After stirring for

15 h at room temperature, the reaction mixture was worked up and

the product purified by filtration through silica gel (hexane/diethyl

ether ϭ 2:1). Ϫ Yield: 10.88 g (75%, red crystals). Ϫ R_fϭ 0.31

(hexane/ethyl acetate ϭ 10:1). Ϫ M.p.: 60 °C. Ϫ IR (KBr): ν˜ ϭ

3114 cm^Ϫ1, 3088, 3081, 2961, 2953, 2937, 2904, 2882, 2864, 2706,

2463, 2406, 2253, 2055, 1702, 1661, 1468, 1451, 1412, 1396, 1375,

1360, 1341, 1294, 1238, 1171, 1135, 1109, 1092, 1065, 1030, 1000,

951, 919, 894, 859, 845, 823, 749, 648, 597, 534, 493, 481, 461. Ϫ

¹H NMR (300 MHz, C₆D₆): δ ϭ 0.98 (dm, ³J ϭ 6.4 Hz, 6 H, CH₃),

2.42 [m, 3 H, OϭCCH₂, CH(CH₃)₂], 3.93 (s, 5 H, C₅H₅), 4.08 (t,

^3/4J ϭ 1.8 Hz, 2 H, m-C₅H₄R), 4.65 (t, ^3/4J ϭ 2.0 Hz, 2 H, o-

C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 23.0 (CH₃), 25.0

[CH(CH₃)₂], 48.8 (OϭCCH₂), 69.6, 71.9 (C₅H₄R), 69.8 (C₅H₅),

80.6 (i-C₅H₄R), 201.9 (CϭO). Ϫ EI-MS; m/z: 270.1 (100) [M^ϩ],

228.1 (36) [M^ϩϪ CH₂ϭCH-CH₃], 213.1 (39) [FcCO^ϩ], 186.1 (29)

[Cp₂Fe^ϩ], 185.0 (61) [Fc^ϩ], 129.1 (51) [C₁₀H₉^ϩ], 120.9 (50) [CpFe^ϩ],

56.0 (13) [Fe^ϩ]. Ϫ C₁₅H₁₈FeO (270.2): calcd. C 66.69, H 6.72;

found C 66.61, H 6.74.

³¹P, respectively), Varian Unity 500 (500, 125, and 202 MHz for

¹H, ¹³C, and ³¹P, respectively), C₆D₆or CDCl₃as solvent, TMS

as internal standard. Ϫ MS: Finnigan MAT (70 eV). Ϫ Elemental

analyses (C,H,N): elementar vario EL. Ϫ High Resolution MS:

Finnigan MAT, MAT 95. Ϫ The diastereomeric excesses were de-

termined by NMR spectroscopy. The enantiomeric excesses were

determined by HPLC employing chiral stationary phases or by

NMR spectroscopy using Pirkle alcohol as chiral co-solvent.

General Procedure for the Preparation of Ferrocenyl Ketones 1

(GP1): To a suspension of AlCl₃(1.06 equiv.) in dichloromethane

(0.5 mL/mmol) was added the acid chloride (1.01 equiv.). The mix-

ture was stirred until the Al salt was dissolved nearly completely.

The resulting solution was added to a solution of ferrocene (1.00

equiv.) in dichloromethane (0.75 mL/mmol). After stirring for the

appropriate time (TLC control) at room temperature, the reaction

mixture was poured onto crushed ice/aqueous saturated NaHCO₃.

The aqueous phase was extracted three times with diethyl ether.

The combined organic phases were washed with saturated aqueous

NaHCO₃and twice with brine. After drying with MgSO₄and con-

centrating in vacuo, the crude product was dissolved in a minimum

of dichloromethane and purified by filtration through silica gel.

1-Ferrocenyl-1-propanone (1a): According to GP1, a solution of

ferrocene (30.00 g, 161.3 mmol) in CH₂Cl₂(120 mL) was treated

with a solution of AlCl₃(22.80 g, 1.06 equiv.) and propionyl chlor-

ide (15.07 g, 1.01 equiv.) in CH₂Cl₂(90 mL). After stirring for 15

h at room temperature, the reaction mixture was worked up and

the product purified by filtration through silica gel (hexane/diethyl

ether ϭ 2:1). Ϫ Yield: 32.17 g (82%, dark red crystals). Ϫ R_fϭ

1-Ferrocenyl-2-phenyl-1-ethanone (1d): According to GP1, a solu-

tion of ferrocene (7.50 g, 40.3 mmol) in CH₂Cl₂(30 mL) was

treated with a solution of AlCl₃(5.64 g, 1.05 equiv.) and phenyl

acetyl chloride (6.29 g, 1.01 equiv.) in CH₂Cl₂(30 mL). After stir-

ring for 15 h at room temperature, the reaction mixture was worked

up and the product purified by filtration through silica gel (hexane/

diethyl ether ϭ 2:1). Ϫ Yield: 7.36 g (60%, red crystals). Ϫ R_fϭ

0.44 (hexane/diethyl ether ϭ 2:1). Ϫ M.p.: 40 °C. Ϫ IR (Et₂O): ν˜ ϭ 0.29 (hexane/diethyl ether ϭ 4:1). Ϫ M.p.: 130 °C. Ϫ IR (KBr):

3096 cm^Ϫ1, 2975, 2936, 2903, 2876, 1670, 1454, 1414, 1398, 1378, ν˜ ϭ 3107 cm^Ϫ1, 3082, 3031, 2882, 1661, 1496, 1445, 1410, 1377,

1353, 1248, 1106, 1099, 1051, 1026, 1002, 962, 880, 823, 531, 495,

1350, 1333, 1317, 1246, 1215, 1202, 1168, 1105, 1068, 1030, 1003,

989, 926, 888, 827, 777, 730, 702, 643, 575, 537, 498, 482, 455. Ϫ

1

3

483, 460. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ 1.17 (t, J ϭ 7.4 Hz,

3

3 H, CH₃), 2.43 (q, J ϭ 7.4 Hz, 2 H, CH₂), 3.90 (s, 5 H, C₅H₅), ¹H NMR (300 MHz, C₆D₆): δ ϭ 3.72 (broad s, 2 H, CH₂), 3.81 (s,

3406

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

3

4

3

5 H, C₅H₅), 4.05 (t, ^3/4J ϭ 2.0 Hz, 2 H, m-C₅H₄R), 4.66 (t, ^3/4J ϭ 4.68 (dt, J ϭ 1.9 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 4.75 (dt, J ϭ

2.0 Hz, 2 H, o-C₅H₄R), 7.06 (tt, J ϭ 7.4 Hz, J ϭ 1.4 Hz, 1 H, p-

3

4

3

4

1.9 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R), [5.27 (dt, J ϭ 2.5 Hz, J ϭ

C₆H₅), 7.16 (m, 2 H, m-C₆H₅), 7.31 (dm, ³J ϭ 8.4 Hz, 2 H, o- 1.4 Hz, 1 H, o-C₅H₄R)]. Ϫ ¹³C NMR [(E) isomer, 75 MHz, C₆D₆]:

C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 47.0 (CH₂), 69.97

(C₅H₅), 70.01, 72.2 (C₅H₄R), 79.7 (i-C₅H₄R), 126.9 (p-C₆H₅),

δ

ϭ

13.0 (CH₃), 22.6 (NCH₂CH₂), 23.6 (CH₂CH₃), 27.6

(NCHCH₂), 55.8 (NCH₂), 58.9 (OCH₃), 66.9 (NCH), 67.6, 68.0,

128.7, 129.8 (o/m-C₆H₅), 136.1 (i-C₆H₅), 200.0 (CϭO). Ϫ EI-MS; 69.8 (C₅H₄R), 69.5 (C₅H₅), 76.5 (OCH₂), 83.3 (i-C₅H₄R), 167.6

m/z: 304.1 (100) [M^ϩ], 213.1 (75) [M^ϩϪ C₇H₇], 186.2 (10) (CϭN). Ϫ ¹³C NMR [(Z) isomer, 75 MHz, C₆D₆]: δ ϭ 13.4 (CH₃),

[Cp₂Fe^ϩ], 185.0 (73) [Fc^ϩ], 129.2 (79) [C₁₀H₉^ϩ], 120.9 (30) [CpFe^ϩ],

22.6 (NCH₂CH₂), 27.4 (NCHCH₂), 30.6 (CH₂CH₃), 53.9 (NCH₂),

91.1 (30) [C₇H₇^ϩ], 65.1 (12) [C₅H₅^ϩ], 56.0 (14) [Fe^ϩ]. Ϫ C₁₈H₁₆FeO 58.9 (OCH₃), 67.2, 69.2, 69.5, 70.7, 71.9 (C₅H₄R, NCH), 69.8

(304.2): C 71.08, H 5.30; found C 71.21, H 5.32.

(C₅H₅), 76.5 (OCH₂), 83.3 (i-C₅H₄R), 161.5 (CϭN). Ϫ EI-MS; m/z:

354.2 (83) [M^ϩ], 309.1 (47) [M^ϩϪ CH₂OCH₃], 240.1 (100) [M^ϩϪ

C₆H₁₂NO], 211.0 (40) [FcCN^ϩ], 186.2 (14) [Cp₂Fe^ϩ], 185.0 (97)

[Fc^ϩ], 154.4 (16) [211.0 Ϫ Fe], 128.9 (35) [C₁₀H₉^ϩ], 121.0 (62)

[CpFe^ϩ], 45.3 (17) [CH₃OCH₂]. Ϫ C₁₉H₂₆FeN₂O (354.3): calcd. C

64.42, H 7.40, N 7.91; found C 64.30, H 7.52, N 7.42.

1,1Ј-Dipropionylferrocene 9: According to GP1, a solution of ferro-

cene (20.00 g, 107.5 mmol) in CH₂Cl₂(100 mL) was treated with a

solution of AlCl₃(31.50 g, 2.20 equiv.) and propionyl chloride

(21.88 g, 2.20 equiv.) in CH₂Cl₂(150 mL). After stirring for 24 h

at room temperature, the reaction mixture was worked up and the

product purified by filtration through silica gel (hexane/diethyl

ether ϭ 2:1). Ϫ Yield: 28.63 g (89%, reddish-black crystals). Ϫ R_fϭ

0.20 (hexane/diethyl ether ϭ 2:1). Ϫ M.p.: 52 °C. Ϫ IR (KBr): ν˜ ϭ

3096 cm^Ϫ1, 3079, 2968, 2933, 2909, 2874, 2377, 2224, 1758, 1673,

1457, 1412, 1375, 1338, 1242, 1100, 1048, 1023, 962, 883, 862, 828,

SAMP-hydrazone 2b: According to GP2, a solution of ketone 1b

(16.80 g, 65.7 mmol) in toluene (50 mL) was added to a solution of

SAMP/AlMe₃(2.0 equiv.) in toluene (50 mL). After heating at re-

flux for 15 h, the reaction mixture was worked up. Purification by

filtration through silica gel provided a mixture of (E)- and (Z)-2b

(hexane/diethyl ether ϭ 4:1; 2% NEt₃). Ϫ Yield: 24.1 g (100%, or-

ange-brown powder). Ϫ (E)/(Z) ϭ 3.1:1. Ϫ R_fϭ 0.50 (petroleum

ether ether/diethyl ether ϭ 6:1; 2% NEt₃). Ϫ [α]²_D⁵ϭ ϩ508.8 [(E)

isomer, CHCl₃, c ϭ 0.91]; [α]²_D⁵ϭ Ϫ375.0 [(Z) isomer, CHCl₃, c ϭ

2.21). Ϫ M.p.: 66 °C. Ϫ IR (KBr): ν˜ ϭ 3083 cm^Ϫ1, 2962, 2932,

2913, 2866, 2821, 2798, 2736, 2252, 1604, 1465, 1455, 1410, 1378,

1343, 1303, 1291, 1276, 1242, 1201, 1183, 1123, 1107, 1058, 1045,

1026, 1002, 974, 914, 854, 817, 758, 699, 670, 618, 592, 500, 459.

Ϫ ¹H NMR [(E) isomer, 300 MHz, C₆D₆]: δ ϭ 0.96 (t, ³J ϭ 7.3 Hz,

3 H, CH₃), 1.60 (m, 1 H, CH₂CH₃), 1.64 (m, 1 H, NCH₂CH₂),

1.73 (m, 1 H, CH₂CH₃), 1.75 (m, 1 H, NCH₂CH₂), 1.78 (m, 1 H,

NCHCH₂), 2.05 (m, 1 H, NCHCH₂), 2.56 (m, 1 H, NCH₂), 2.58

(m, 1 H, NϭCCH₂), 2.65 (m, 1 H, NϭCCH₂), 3.10 (m, 1 H,

1

807, 703, 644, 591, 534, 506, 474. Ϫ H NMR (300 MHz, CDCl₃):

δ ϭ 1.17 (t, ³J ϭ 7.4 Hz, 6 H, CH₃), 2.74 (q, ³J ϭ 7.4 Hz, 4 H,

CH₂), 4.53 (t, ^3/4J ϭ 1.9 Hz, 4 H, m-C₅H₄R), 4.84 (t, ^3/4J ϭ 1.9 Hz,

4 H, o-C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 7.8 (CH₃), 32.7

(CH₂), 70.2, 72.9 (C₅H₄R), 79.9 (i-C₅H₄R), 203.8 (CϭO). Ϫ EI-

MS; m/z: 297.9 (100) [M^ϩ], 268.8 (37) [M^ϩϪ CH₂CH₃], 212.7 (25)

[268.8 Ϫ Fe], 184.9 (11) [Fc^ϩ], 120.6 (13) [CpFe^ϩ]. Ϫ C₁₆H₁₈FeO₂

(298.2): calcd. C 64.45, H 6.09; found C 64.45, H 6.22.

General Procedure for the Preparation of Hydrazones 2 (GP2): A

Schlenk flask with an attached reflux condenser and a silicon

bubbler was charged under argon with AlMe₃(2.0 equiv., 2  in

toluene, 1Ϫ2 mL/mmol). Then SAMP (2.0 equiv.) was added

slowly. After the evolution of methane subsided, the mixture was

heated at reflux for 7 h. Ferrocenyl ketone 1 (1.0 equiv.), dissolved

in toluene (1Ϫ2 mL/mmol), was added dropwise to the red-brown

solution. The mixture was heated at reflux until completion (TLC

control), cooled down to 0 °C, poured onto crushed ice and washed

with 5% aqueous NaHCO₃and brine, dried with MgSO₄, and con-

centrated in vacuo. The crude product was purified by filtration

through silica gel.

2

3

NCH₂), 3.20 (s, 3 H, OCH₃), 3.36 (dd, J ϭ 8.5 Hz, J ϭ 7.4 Hz,

1 H, OCH₂), 3.55 (m, 1 H, NCH), 3.64 (dd, ²J ϭ 8.5 Hz, ³J ϭ

3.8 Hz, 1 H, OCH₂), 4.05 (s, 5 H, C₅H₅), 4.12 (t, ³J ϭ 1.8 Hz, 2

H, m-C₅H₄R), 4.66 (m, 1 H, o-C₅H₄R), 4.80 (m, 1 H, o-C₅H₄R).

Ϫ ¹H NMR [(Z) isomer, 300 MHz, C₆D₆]: δ ϭ 1.06 (t, ³J ϭ 7.4 Hz,

3 H, CH₃), 1.56 (m, 1 H, NCH₂CH₂), 1.65 (m, 1 H, NCH₂CH₂),

3

1.76 (m, 1 H, NCHCH₂), 1.85 (sext, J ϭ 7.4 Hz, 2 H, CH₂CH₃),

3

2.00 (m, 1 H, NCHCH₂), 2.33 (q, J ϭ 7.4 Hz, 1 H, NCH₂), 2.57

SAMP-hydrazone 2a: According to GP2, a solution of ketone 1a

(4.00 g, 16.5 mmol) in toluene (40 mL) was added to a solution of

SAMP/AlMe₃(2.0 equiv.) in toluene (40 mL). After heating at re-

flux for 15 h, the reaction mixture was worked up. Purification by

filtration through silica gel provided a mixture of (E)- and (Z)-2a

(hexane/diethyl ether ϭ 4:1; 2% NEt₃). Ϫ Yield: 5.57 g (95%, or-

ange-brown powder). Ϫ (E)/(Z) ϭ 2.8:1. Ϫ R_fϭ 0.23 (hexane/di-

ethyl ether ϭ 10:1; 2% NEt₃). Ϫ [α]²_D⁵ϭ ϩ266.3 (CHCl₃, c ϭ 1.66).

Ϫ M.p.: 55 °C. Ϫ IR (KBr): ν˜ ϭ 3088 cm^Ϫ1, 2966, 2932, 2869,

2824, 2804, 2726, 2371, 2232, 1674, 1637, 1601, 1458, 1411, 1381,

1339, 1301, 1277, 1245, 1199, 1187, 1121, 1106, 1042, 1001, 975,

915, 878, 819, 707, 610, 502. Ϫ ¹H NMR {(E) isomer [(Z) isomer],

300 MHz, C₆D₆}: δ ϭ 1.17 (t, ³J ϭ 7.7 Hz, 3 H, CH₃), [1.35 (t,

³J ϭ 7.4 Hz, 3 H, CH₃)], 1.55Ϫ1.83 (m, 3 H, β-ring-CH₂), 2.04 (m,

1 H, β-ring-CH₂), 2.53 (m, 2 H, CH₂CH₃), 2.69 (m, 1 H, NCH₂),

3.09 (m, 1 H, NCH₂), 3.20 (s, 3 H, OCH₃), [3.24 (s, 3 H, OCH₃)],

(m, 1 H, NϭCCH₂), 2.64 (m, 1 H, NϭCCH₂), 3.18 (m, 1 H,

NCH₂), 3.24 (s, 3 H, OCH₃), 3.42 (m, 1 H, OCH₂), 3.53 (m, 1 H,

2

3

NCH), 3.68 (dd, J ϭ 8.7 Hz, J ϭ 3.7 Hz, 1 H, OCH₂), 4.03 (s, 5

H, C₅H₅), 4.09 (m, 1 H, m-C₅H₄R), 4.15 (m, 1 H, m-C₅H₄R), 4.45

(m, 1 H, o-C₅H₄R), 5.29 (m, 1 H, o-C₅H₄R). Ϫ ¹³C NMR [(E)

isomer, 75 MHz, C₆D₆]: δ ϭ 15.0 (CH₃), 21.9 (CH₂CH₃), 22.6

(NCH₂CH₂), 27.7 (NCHCH₂), 32.8 (NϭCCH₂), 55.7 (NCH₂), 58.9

(OCH₃), 67.0, 67.7, 68.2, 69.77, 69.83 (C₅H₄R, NCH), 69.6 (C₅H₅),

76.6 (OCH₂), 83.8 (i-C₅H₄R), 166.4 (CϭN). Ϫ ¹³C NMR [(Z) iso-

mer, 75 MHz, C₆D₆): δ ϭ 14.4 (CH₃), 22.2 (NCH₂CH₂), 22.6

(CH₂CH₃), 27.3 (NCHCH₂), 39.4 (NϭCCH₂), 53.9 (NCH₂), 58.9

(OCH₃), 67.1, 69.2, 69.8, 70.7, 71.9 (C₅H₄R, NCH), 69.7 (C₅H₅),

76.5 (OCH₂), 78.6 (i-C₅H₄R), 160.5 (CϭN). Ϫ EI-MS; m/z: 368.0

(61) [M^ϩ], 322.9 (36) [M^ϩϪ CH₂OCH₃], 253.9 (100) [M^ϩ

C₆H₁₂NO], 210.9 (31) [FcCN^ϩ], 184.8 (79) [Fc^ϩ], 161.3 (12), 129.0

(37) [Fc^ϩFe], 120.8 (44) [CpFe^ϩ], 55.9 (13) [Fe^ϩ].

Ϫ

2

3

[3.28 (m, 1 H, NCH₂)], 3.35 (dd, J ϭ 8.5 Hz, J ϭ 7.4 Hz, 1 H,

C₂₀H₂₈FeN₂O (368.3): calcd. C 65.22, H 7.66, N 7.61; found C

65.21, H 7.39, N 7.50.

OCH₂), [3.43 (dd, ²J ϭ 8.8 Hz, ³J ϭ 7.1 Hz, 1 H, OCH₂)], 3.54

3

2

(qd, J ϭ 7.7 Hz, J ϭ 4.1 Hz, 1 H, NCH), 3.63 (dd, J ϭ 8.7 Hz,

³J ϭ 4.1 Hz, 1 H, OCH₂), [3.69 (dd, J ϭ 8.7 Hz, J ϭ 3.8 Hz, 1

SAMP-hydrazone 2c: According to GP2, a solution of ketone 1c

2

3

H, OCH₂)], [4.01 (s, 5 H, C₅H₅)], 4.05 (s, 5 H, C₅H₅), 4.12 (m, 2 (16.80 g, 65.7 mmol) in toluene (50 mL) was added to a solution of

H, m-C₅H₄R), [4.42 (dt, ³J ϭ 2.8 Hz, ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R)],

SAMP/AlMe₃(2.0 equiv.) in toluene (50 mL). After heating at re-

3407

Eur. J. Org. Chem. 2000, 3399Ϫ3426

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

3

4

flux for 15 h, the reaction mixture was worked up. Purification by

filtration through silica gel provided a mixture of (E)- and (Z)-2c

(hexane/diethyl ether ϭ 4:1; 2% NEt₃). Ϫ Yield: 5.97 g (84%, red

1 H, o-C₅H₄R)], 7.03 (tt, J ϭ 7.4 Hz, J ϭ 1.5 Hz, 1 H, p-C₆H₅),

3

7.14 (m, 2 H, m-C₆H₅), 7.27 (dm, J ϭ 7.4 Hz, 2 H, o-C₆H₅), [7.45

(broad d, ³J ϭ 7.4 Hz, 2 H, o-C₆H₅)]. Ϫ ¹³C NMR [(E) isomer,

oil). Ϫ R_fϭ 0.39 (hexane/diethyl ether ϭ 4:1). Ϫ (E)/(Z) ϭ 2.2:1. 75 MHz, C₆D₆]: δ ϭ 22.5 (NCH₂CH₂), 27.3 (NCHCH₂), 36.4 (Nϭ

Ϫ [α]²_D⁵ϭ Ϫ33.5 (CHCl₃, c ϭ 2.38). Ϫ IR (CHCl₃): ν˜ ϭ 3094 cm^Ϫ1

2955, 2925, 2869, 2826, 2728, 1670, 1595, 1462, 1383, 1367, 1340,

,

CCH₂), 55.6 (NCH₂), 58.9 (OCH₃), 66.9, 68.3, 68.6, 69.8, 69.9

(NCH, C₅H₄R), 69.6 (C₅H₅), 76.3 (OCH₂), 83.8 (i-C₅H₄R), 126.2

1298, 1197, 1166, 1107, 1051, 1028, 1001, 971, 917, 894, 819, 756, (p-C₆H₅), 128.7, 128.8 (o/m-C₆H₅), 139.2 (i-C₆H₅), 164.2 (CϭN).

1

497. Ϫ H NMR {(E) isomer [(Z) isomer], 300 MHz, C₆D₆}: δ ϭ

Ϫ

¹³C NMR [(Z) isomer, 75 MHz, C₆D₆]: δ ϭ 22.7 (NCH₂CH₂),

0.97 (d, J ϭ 6.7 Hz, 3 H, CH₃), 0.98 (d, J ϭ 6.7 Hz, 3 H, CH₃), 27.4 (NCHCH₂), 44.6 (NϭCCH₂), 54.1 (NCH₂), 59.0 (OCH₃), 67.3

[1.05 (d, ³J ϭ 6.7 Hz, 3 H, CH₃)], [1.10 (d, ³J ϭ 6.7 Hz, 3 H, CH₃)],

(NCH), 69.4, 69.7, 71.3, 72.0 (C₅H₄R), 69.9 (C₅H₅), 76.6 (OCH₂),

1.54 Ϫ 1.81 (m, 3 H, β-ring-CH₂), 2.06 (m, 1 H, β-ring-CH₂), 2.28 78.6 (i-C₅H₄R), 126.5 (p-C₆H₅), 128.7, 128.8 (o/m-C₆H₅). Ϫ EI-

3

2

3

(non, J ϭ 6.7 Hz, 1 H, CH(CH₃)₂), 2.41 (dd, J ϭ 12.8 Hz, J ϭ

MS; m/z: 416.2 (66) [M^ϩ], 371.1 (26) [M^ϩϪ CH₂OCH₃], 302.0 (51)

7.1 Hz, 1 H, NϭCCH₂), 2.68 (dd, J ϭ 12.8 Hz, ³J ϭ 7.7 Hz, 1 H, [M^ϩϪ C₆H₁₂NO], 211.1 (100) [FcCN^ϩ], 185.0 (26) [Fc^ϩ], 129.2

2

NϭCCH₂), 3.18 (s, 3 H, OCH₃), 3.23 (m, 1 H, NCH₂), [3.24 (s, 3

(10) [C₁₀H₉^ϩ], 121.0 (50) [CpFe^ϩ], 91.1 (39) [C₇H₇^ϩ].

C₂₄H₂₈FeN₂O (416.3): calcd. C 69.23, H 6.78, N 6.73; found C

Ϫ

H, OCH₃)], 3.32 (dd, J ϭ 8.7 Hz, ³J ϭ 7.7 Hz, 1 H, OCH₂), [3.44

2

3

(dd, J ϭ 8.7 Hz, J ϭ 7.4 Hz, 1 H, OCH₂)], 3.52 (m, 1 H, NCH), 68.89, H 7.05, N 6.73.

2

3

2

3.62 (dd, J ϭ 8.7 Hz, J ϭ 4.0 Hz, 1 H, OCH₂), [3.69 (dd, J ϭ

SAMP-bis(hydrazone) 10: According to GP2, a solution of dike-

tone 9 (10.00 g, 33.5 mmol) in toluene (30 mL) was added to a solu-

tion of SAMP/AlMe₃(4.0 equiv.) in toluene (100 mL). After heat-

ing at reflux for 15 h, the reaction mixture was worked up. Purifica-

tion by filtration through silica gel provided a mixture of (E,E)-,

(E,Z)-, and (Z,Z)-10 (hexane/diethyl ether ϭ 4:1). Ϫ Yield: 16.00 g

(91%, red oil). Ϫ R_fϭ 0.23 (hexane/diethyl ether ϭ 4:1). Ϫ (EE)/

(EZ)/(ZZ) ϭ 4.5:1.5:1. Ϫ IR (CHCl₃): ν˜ϭ 3093 cm^Ϫ1, 2971, 2935,

2874, 2826, 2732, 1676, 1642, 1600, 1550, 1451, 1379, 1345, 1316,

1295, 1278, 1247, 1198, 1109, 1046, 1027, 970, 914, 881, 829, 755,

665, 507. Ϫ ¹H NMR [(E,E) isomer, 400 MHz, C₆D₆]: δ ϭ 1.18 (t,

³J ϭ 7.7 Hz, 6 H, CH₃), 1.60Ϫ2.12 (m, 12 H, β-ring-CH₂,

CH₂CH₃), 2.59 (m, 1 H, NCH₂), 3.13 (m, 1 H, NCH₂), 3.21 (s, 6

3

9.1 Hz, J ϭ 3.7 Hz, 1 H, OCH₂)], [4.03 (s, 5 H, C₅H₅)], 4.06 (s, 5

3

4

H, C₅H₅), 4.13 (m, 2 H, m-C₅H₄R), [4.46 (dt, J ϭ 2.7 Hz, J ϭ

3

4

1.3 Hz, 1 H, o-C₅H₄R),], 4.55 (dt, J ϭ 2.4 Hz, J ϭ 1.3 Hz, 1 H,

o-C₅H₄R), 4.94 (dt, ³J ϭ 2.7 Hz, ⁴J ϭ 1.3 Hz, 1 H, o-C₅H₄R), [5.30

(dt, J ϭ 2.4, J ϭ 1.4, 1 H, o-C₅H₄R)]. Ϫ ¹³C NMR [(E) isomer,

75 MHz, C₆D₆]: δ ϭ 22.5 (NCH₂CH₂), 22.9, 23.3 (CH₃), 27.3

[CH(CH₃)₂], 27.7 (NCHCH₂), 39.5 (NϭCCH₂), 55.2 (NCH₂), 58.8

(OCH₃), 67.0, 67.8, 68.4, 69.6, 69.9 (C₅H₄R, NCH), 69.6 (C₅H₅),

76.5 (OCH₂), 84.4 (i-C₅H₄R), 165.6 (CϭN). Ϫ ¹³C NMR [(Z) iso-

mer, 75 MHz, C₆D₆]: δ ϭ 22.6 (NCH₂CH₂), 22.8, 23.4 (CH₃), 27.7

(NCHCH₂), 27.8 [CH(CH₃)₂], 46.4 (NϭCCH₂), 54.0 (NCH₂), 59.0

(OCH₃), 67.2, 69.3, 69.9, 70.8, 72.1 (C₅H₄R, NCH), 69.8 (C₅H₅),

76.6 (OCH₂), 79.0 (i-C₅H₄R), 159.8 (CϭN). Ϫ EI-MS; m/z: 382.2

3

4

2

3

H, OCH₃), 3.34 (dd, J ϭ 8.8 Hz, J ϭ 7.4 Hz, 2 H, OCH₂), 3.55

(48) [M^ϩ], 337.1 (28) [M^ϩϪ H₂COCH₃], 269.1 (21) [M^ϩ

Ϫ

3

2

(qd, J ϭ 7.4 Hz, J ϭ 4.1 Hz, 2 H, NCH), 3.63 (dd, J ϭ 8.8 Hz,

³J ϭ 4.1 Hz, 2 H, OCH₂), 4.18 (td, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 2 H,

C₅H₄R), 4.20 (td, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 2 H, C₅H₄R), 4.68 (dt,

³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 2 H, C₅H₄R), 4.70 (dt, ³J ϭ 2.5 Hz, ⁴J ϭ

1.4 Hz, 2 H, C₅H₄R). Ϫ ¹³C NMR [(E,E) isomer, 100 MHz, C₆D₆]:

δ ϭ 12.9 (CH₃), 22.7, 23.7 (CH₂), 27.7 (NCHCH₂), 55.9 (NCH₂),

58.9 (OCH₃), 67.0, 68.7, 69.1, 71.2, 71.4 (C₅H₄R, NCH), 76.6

(OCH₂), 84.3 (i-C₅H₄R), 166.7 (CϭN). Ϫ EI-MS; m/z: 522.3 (100)

[M^ϩ], 408.2 (12) [M^ϩϪ C₆H₁₂NO], 289.1 (96) [M^ϩϪ C₅H₄R],

280.1 (49) [408.2 Ϫ C₆H₁₂N₂O], 244.1 (44) [289.1 Ϫ OCH₃], 234.1

(20) [C₅H₄R^ϩ], 216.1 (40) [280.1 Ϫ C₅H₄], 205.9 (17), 188.9 (27),

181.6 (44), 147.0 (51). Ϫ C₂₈H₄₂FeN₄O₂(522.5): calcd. C 64.36, H

8.10, N 10.72; found C 64.36, H 8.23, N 10.33.

C₆H₁₁NO], 268.1 (92) [M^ϩϪ C₆H₁₂NO], 212.0 (14) [FcCNH^ϩ],

211.0 (31) [FcCN^ϩ], 202.0 (13) [268.1 Ϫ C₅H₆], 186.0 (24)

[Cp₂Fe^ϩ], 185.0 (100) [Fc^ϩ], 168.7 (15), 149.0 (18), 129.1 (64)

[C₁₀H₉^ϩ], 128.1 (13), 121.0 (73) [CpFe^ϩ], 91.1 (14), 71.2 (12), 70.2

(15), 57.2 (16) [CH₂CH(CH₃)₂^ϩ], 56.1 (20) [Fe^ϩ], 55.2 (14), 45.3

(20) [H₃COCH₂^ϩ]. Ϫ C₂₁H₃₀FeN₂O (382.3): calcd. C 65.97, H 7.91,

N 7.33; found C 65.96, H 8.16, N 7.03.

SAMP-hydrazone 2d: According to GP2, a solution of ketone 1d

(3.00 g, 9.86 mmol) in toluene (50 mL) was added to a solution of

SAMP/AlMe₃(2.0 equiv.) in toluene (30 mL). After heating at re-

flux for 15 h, the reaction mixture was worked up. Purification by

filtration through silica gel provided a mixture of (E)- and (Z)-2d

(hexane/diethyl ether ϭ 4:1; 2% NEt₃). Ϫ Yield: 3.15 g (77%, or-

ange-brown powder). Ϫ R_fϭ 0.29 (hexane/diethyl ether ϭ 4:1; 2%

NEt₃). Ϫ (E)/(Z) ϭ 4.3:1. Ϫ [α]²_D⁵ϭ ϩ415.7 (CHCl₃, c ϭ 1.38). Ϫ

M.p.: 92 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3085 cm^Ϫ1, 3060, 3025, 2970,

2922, 2872, 2826, 2730, 1766, 1664, 1595, 1582, 1494, 1453, 1382,

1342, 1298, 1196, 1186, 1106, 1076, 1054, 1031, 1002, 971, 913,

899, 876, 820, 754, 713, 666, 547, 489. Ϫ ¹H NMR {(E) isomer,

[(Z) isomer], (300 MHz, C₆D₆): δ ϭ 1.46Ϫ1.82 (m, 3 H, β-ring-

CH₂), 1.99 (m, 1 H, β-ring-CH₂), [2.42 (m, 1 H, NCH₂)], 2.55 (q,

General Procedure for the Preparation of Hydrazones 3 (GP3): A

heated Schlenk flask was charged under argon with 1.2 equiv. diiso-

propylamine in dry diethyl ether (3 mL mmol^Ϫ1) at 0 °C. A solution

of 1.2 equiv. nBuLi (1.5  in hexane) was added dropwise. After

20 min, a LiClO₄solution (4 , 3 equiv.) in diethyl ether was in-

jected. After stirring for a further 10 min, a solution of the hy-

drazone 2 in diethyl ether (2.5 mL mmol^Ϫ1) was added and the

cooling bath was removed. The orange-brown solution was stirred

for 6 h at room temperature, and then cooled to Ϫ100 °C.

2

3

^2/3J ϭ 8.8 Hz, 1 H, NCH₂), 2.96 (ddd, J ϭ 10.9 Hz, J ϭ 7.4 Hz,

³J ϭ 3.7 Hz, 1 H, NCH₂), 3.22 (s, 3 H, OCH₃), [3.25 (s, 3 H,

OCH₃)], 3.36 (dd, ²J ϭ 8.4 Hz, ³J ϭ 6.7 Hz, 1 H, OCH₂), [3.48

Method A: Introduction of the Alkyl or Sulfur Substituent E¹: The

alkyl halide or the disulfide (1.4 equiv.) was added dropwise to the

azaenolate solution. The cooling bath was filled with dry ice. After

warming to room temperature overnight, the solution was cooled

to 0 °C and quenched with saturated aqueous NH₄Cl, washed twice

with brine and dried with MgSO₄. The crude product was filtered

through silica gel and dried under high vacuum.

2

3

(dd, J ϭ 8.7 Hz, J ϭ 7.1 Hz, 1 H, OCH₂)], 3.58 (m, 1 H, NCH),

2

3

2

3.63 (dd, J ϭ 8.7 Hz, J ϭ 4.0 Hz, 1 H, OCH₂), [3.73 (dd, J ϭ

8.7 Hz, ³J ϭ 4.0 Hz, 1 H, OCH₂)], [3.96 (m, 2 H, m-C₅H₄R)], [3.97

(s, 5 H, C₅H₅)], 4.02 (s, 5 H, C₅H₅), 4.04 (m, 2 H, m-C₅H₄R), 4.09

(d, ²J ϭ 15.0 Hz, 1 H, NϭCCH₂), 4.17 (d, ²J ϭ 14.8, 1 H, Nϭ

3

4

CCH₂), [4.50 (dt, J ϭ 2.7 Hz, J ϭ 1.3 Hz, 1 H, o-C₅H₄R),], 4.63

(dt, ³J ϭ 2.7 Hz, ⁴J ϭ 1.3 Hz, 1 H, o-C₅H₄R), 4.80 (dt, ³J ϭ 2.4 Hz,

Method B: Introduction of the Phosphorus Substituent E¹: Ph₂PCl

⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R), [5.27 (dt, J ϭ 2.7 Hz, J ϭ 1.3 Hz, (1.3 equiv.) was stirred for 30 min with BH₃DMS (1.3 equiv.) in

3

4

3408

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

diethyl ether (1 mL mmol^Ϫ1) at 0 °C. The resulting solution was

added dropwise to the azaenolate solution at Ϫ100 °C. The cooling

bath was filled with dry ice and subsequently allowed to reach Ϫ20

°C overnight. The reaction mixture was quenched with saturated

aqueous NaHCO₃, washed twice with brine (0 °C) and dried with

MgSO₄at 0 °C. The crude product was filtered through silica gel

and then crystallized from hexane at Ϫ26 °C.

NMR). Ϫ IR (CHCl₃): ν˜ ϭ 3083 cm^Ϫ1, 3057, 3023, 2972, 2921,

2871, 2825, 2731, 2227, 1744, 1700, 1655, 1600, 1571, 1494, 1458,

1409, 1378, 1338, 1295, 1259, 1185, 1106, 1046, 1022, 1000, 962,

910, 883, 825, 751, 698, 674, 640, 590, 561. Ϫ ¹H NMR (major

isomer [minor isomer], 300 MHz, C₆D₆): δ ϭ 1.53 (d, ³J ϭ 7.4 Hz,

3

3 H, CH₃), [1.59 (d, J ϭ 7.1 Hz, 3 H, CH₃)], 1.55Ϫ1.80 (m, 3 H,

β-ring-CH₂), 2.01 (m, 1 H, β-ring-CH₂), 2.54 (q, ^2/3J ϭ 8.5 Hz, 1

H, NCH₂), [2.75 (q, 1 H, ^2/3J ϭ 8.5 Hz, NCH₂)], 3.01 (m, 1 H,

NCH₂), [3.06 (m, 1 H, NCH₂)], [3.23 (s, 3 H, OCH₃)], 3.26 (s, 3 H,

OCH₃), 3.32Ϫ3.74 (m, 3 H, NCH, OCH₂), 3.93 (m, 2 H, m-

SAMP-hydrazone 3a: According to GP3A, a solution of LDA (1.1

equiv.) and LiClO₄(3.3 equiv.) in diethyl ether (2.5 mL) was treated

with a solution of hydrazone 2b (201 mg, 0.546 mmol) in diethyl

ether (2 mL). After cooling to Ϫ100 °C, methyl iodide was added

(51 µL, 1.5 equiv.). Aqueous work up and purification by filtration

through silica gel (hexane/diethyl ether ϭ 4:1) provided hydrazone

3a. Ϫ Yield: 195 mg (93%, yellow crystals). Ϫ R_fϭ 0.39 (hexane/

3

4

C₅H₄R), 3.95 (s, 5 H, C₅H₅), [4.52 (dt, J ϭ 2.7 Hz, J ϭ 1.4 Hz,

1 H, o-C₅H₄R)], 4.56 (dt, ³J ϭ 2.7 Hz, ⁴J ϭ 1.0 Hz, 1 H, o-C₅H₄R),

4.61 (dt, J ϭ 2.4 Hz, J ϭ 1.3 Hz, 1 H, o-C₅H₄R), [4.62 (dt, J ϭ

3

4

3

4

3

2.7 Hz, J ϭ 1.3 Hz, 1 H, o-C₅H₄R),], 5.32 (q, J ϭ 7.4 Hz, 1 H,

CHCH₃), [5.47 (q, ³J ϭ 7.1 Hz, 1 H, CHCH₃),], 7.08 (t, ³J ϭ

7.2 Hz, 1 H, p-C₆H₅), 7.23 (m, 2 H, C₆H₅), [7.33 (dm, ³J ϭ 8.4 Hz,

diethyl ether ϭ 4:1). Ϫ (E)/(Z) ϭ 54:1. Ϫ de Ն 96%. Ϫ [α]²_D⁵

ϭ

2 H, o-C₆H₅)], 7.41 (dm, J ϭ 8.4 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR

3

ϩ521.3 (CHCl₃, c ϭ 1.03). Ϫ M.p.: 25 °C. Ϫ IR (KBr): ν˜ ϭ 3108

cm^Ϫ1, 3088, 2959, 2926, 2872, 2835, 2811, 2730, 2327, 2238, 2056,

1773, 1702, 1639, 1579, 1498, 1459, 1410, 1382, 1350, 1337, 1297,

1279, 1248, 1198, 1185, 1123, 1098, 1046, 1002, 968, 913, 882, 821,

790, 674, 645, 541, 518, 495, 481. Ϫ ¹H NMR [(E,2R) isomer,

500 MHz, C₆D₆]: δ ϭ 0.87 (t, ³J ϭ 7.3 Hz, 3 H, CH₂CH₃), 1.23 (d,

(major isomer, 300 MHz, C₆D₆): δ ϭ 16.3 (CH₃), 22.5 (NCH₂CH₂),

27.3 (NCHCH₂), 37.8 (CHCH₃), 55.8 (NCH₂), 58.8 (OCH₃), 66.9,

67.8, 68.9, 69.0, 70.6 (C₅H₄R, NCH), 70.0 (C₅H₅), 76.8 (OCH₂),

81.3 (i-C₅H₄R), 126.2 (p-C₆H₅), 127.6, 128.4 (o/m-C₆H₅), 142.8 (i-

C₆H₅), 170.0 (CϭN). Ϫ ¹³C NMR (300 MHz, C₆D₆): δ ϭ 17.5

(CH₃), 22.2 (NCH₂CH₂), 27.3 (NCHCH₂), 38.4 (CHCH₃), 56.0

(NCH₂), 58.9 (OCH₃), 66.6, 68.7, 69.6, 69.8, 70.3 (NCH, C₅H₄R),

70.0 (C₅H₅), 76.3 (OCH₂), 81.2 (i-C₅H₄R), 126.2 (p-C₆H₅), 127.5,

128.5 (o/m-C₆H₅), 143.1 (i-C₆H₅), 172.2 (CϭN). Ϫ EI-MS; m/z:

2

3

³J ϭ 7.0 Hz, 3 H, CHCH₃), 1.55 (ddq, J ϭ 15.9 Hz, J ϭ 8.6 Hz,

³J ϭ 7.3 Hz, 1 H, CH₂CH₃), 1.60Ϫ1.80 (m, 4 H, CH₂CH₃,

NCH₂CH₂, NCHCH₂), 2.06 (m, 1 H, NCHCH₂), 2.57 (dt, ²J ϭ

8.9 Hz, ³J ϭ 8.6 Hz, 1 H, NCH₂), 2.99 (ddd, ²J ϭ 9.1 Hz, ³J ϭ

3

430.3 (81) [M^ϩ], 385.2 (33) [M^ϩϪ CH₂OCH₃], 316.1 (55) [M^ϩ

Ϫ

7.6 Hz, J ϭ 3.7 Hz, 1 H, NCH₂), 3.22 (s, 3 H, OCH₃), 3.34 (dd,

²J ϭ 8.9 Hz, ³J ϭ 7.3 Hz, 1 H, OCH₂), 3.45 (qd, ³J ϭ 7.6 Hz, ⁴J ϭ

4.0 Hz, 1 H, NCH), 3.58 (dd, ²J ϭ 8.9 Hz, ³J ϭ 4.0 Hz, 1 H,

C₆H₁₂NO], 252.2 (11), 230.1 (16), 215.0 (27), 212.1 (36), 211.1 (97)

[FcCN^ϩ], 192.6 (11), 184.9 (10) [Fc^ϩ], 170.1 (10), 121.1 (39)

[CpFe^ϩ], 105.1 (100) [PhCHCH₃^ϩ]. Ϫ C₂₅H₃₀FeN₂O (430.4): calcd.

C 69.77, H 7.03, N 6.51; found C 69.30, H 6.67, N 6.39.

3

OCH₂), 3.70 (dq, J ϭ 8.6 Hz, J ϭ 7.0 Hz, 1 H, NϭCCH), 4.11

(s, 5 H, C₅H₅), 4.12 (m, 2 H, m-C₅H₄R), 4.73 (dt, ³J ϭ 1.8 Hz,

⁴J ϭ 1.5 Hz, 1 H, o-C₅H₄R), 4.81 (dt, J ϭ 1.8 Hz, J ϭ 1.5 Hz, 1

H, o-C₅H₄R). Ϫ ¹H NMR [(Z,2S) isomer, 300 MHz, C₆D₆]: δ ϭ

0.86 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.27 (d, ³J ϭ 7.1 Hz, 3 H,

CHCH₃), 1.35Ϫ1.83 (m, 5 H, CH₂CH₃, β-ring-CH₂), 2.06 (m, 1 H,

β-ring-CH₂), 2.47 (q, ^2/3J ϭ 8.8 Hz, 1 H, NCH₂), 3.03 (m, 1 H,

3

4

SAMP-hydrazone 3c: According to GP3B, a solution of LDA (1.15

equiv.) and LiClO₄(4.0 equiv.) in diethyl ether (2 mL) was treated

with a solution of hydrazone 2a (310 mg, 0.875 mmol) in diethyl

ether (3 mL). After cooling to Ϫ100 °C, a solution of Ph₂PCl·BH₃

(1.25 equiv.) in diethyl ether (1 mL) was added dropwise. Aqueous

work up, purification by filtration through silica gel (hexane/diethyl

ether ϭ 4:1) and crystallization from hexane at Ϫ26 °C provided

hydrazone 3c. Ϫ Yield: 440 mg (91%, red crystals). Ϫ R_fϭ 0.30

(hexane/diethyl ether ϭ 4:1). Ϫ (E)/(Z) ϭ 20:1. Ϫ de Ն 96%. Ϫ

[α]²_D⁵ϭ Ϫ86.9 (CHCl₃, c ϭ 1.05). Ϫ M.p.: 104 °C. Ϫ IR (neat):

ν˜ ϭ 3095 cm^Ϫ1, 3082, 3056, 2973, 2934, 2875, 2829, 2734, 2388,

2285, 2107, 1659, 1589, 1565, 1462, 1438, 1415, 1385, 1352, 1338,

1300, 1281, 1250, 1185, 1160, 1124, 1106, 1055, 1030, 1001, 971,

2

3

NCH₂), 3.19 (s, 3 H, OCH₃), 3.32 (dd, J ϭ 8.7 Hz, J ϭ 7.1 Hz,

1 H, OCH₂), 3.57 (m, 1 H, NCH), 3.62 (dd, ²J ϭ 8.5 Hz, ³J ϭ

4.1 Hz, 1 H, OCH₂), 3.69 (m, 1 H, NϭCCH), 4.08 (s, 5 H, C₅H₅),

3

4

4.10 (m, 2 H, m-C₅H₄R), 4.53 (dt, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H,

3

4

o-C₅H₄R), 5.04 (dt, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R). Ϫ

¹³C NMR [(E,2R) isomer, 75 MHz, C₆D₆]: δ ϭ 13.2, 18.4 (CH₃),

22.3 (NCH₂CH₂), 27.5 (NCHCH₂), 27.7 (CH₂CH₃), 36.4

(CHCH₃), 56.0 (NCH₂), 58.9 (OCH₃), 66.8 (NCH), 68.6, 69.5 (o-

C₅H₄R), 69.0, 69.2 (m-C₅H₄R), 69.8 (C₅H₅), 76.4 (OCH₂), 81.5 (i-

C₅H₄R), 172.6 (CϭN). Ϫ ¹³C NMR [(Z,2S) isomer, 75 MHz,

C₆D₆]: δ ϭ 12.6, 18.9 (CH₃), 22.4 (NCH₂CH₂), 27.6 (NCHCH₂),

28.7 (CH₂CH₃), 36.5 (CHCH₃), 55.8 (NCH₂), 58.8 (OCH₃), 67.0

(NCH), 68.4, 69.0, 69.1 (C₅H₄R), 69.9 (C₅H₅), 76.7 (OCH₂), 81.4

(i-C₅H₄R), 170.5 (CϭN). Ϫ EI-MS; m/z: 382.1 (70) [M^ϩ], 337.1

(38) [M^ϩϪ CH₂OCH₃], 317.1 (19) [M^ϩϪ C₅H₅], 268.0 (100) [M^ϩ

Ϫ C₆H₁₂NO], 210.9 (36) [FcCN^ϩ], 184.9 (45) [Fc^ϩ], 129.0 (29)

[C₁₀H₉^ϩ], 120.9 (38) [CpFe^ϩ], 57.1 (10) [FeH^ϩ], 45.3 (10)

[CH₃OCH₂^ϩ]. Ϫ C₂₁H₃₀FeN₂O (382.3): calcd. C 65.97, H 7.91, N

7.33; found C 65.94, H 7.91, N 7.57.

911, 883, 821, 739, 699, 644, 609, 547, 500. Ϫ ¹H NMR (300 MHz,

3

C₆D₆): δ ϭ 1.53Ϫ1.73 (m, 3 H, β-ring-CH₂), 1.79 (dd, J_HP

ϭ

3

17.0 Hz, J ϭ 7.7 Hz, 3 H, CH₃), 2.00 (m, 1 H, β-ring-CH₂), 2.37

(q, ^2/3J ϭ 8.5 Hz, 1 H, NCH₂), 3.03 (m, 1 H, NCH₂), 3.12 (s, 3 H,

OCH₃), 3.13 (dd, J ϭ 9.3 Hz, ³J ϭ 7.2 Hz, 1 H, OCH₂), 3.20 (dd,

2

²J ϭ 9.1 Hz, ³J ϭ 4.1 Hz, 1 H, OCH₂), 3.52 (qd, ³J ϭ 7.4 Hz, ³J ϭ

4.1 Hz, 1 H, NCH), 3.92 (s, 5 H, C₅H₅), 3.99 (td, ³J ϭ 2.2 Hz, ⁴J ϭ

1.1 Hz, 1 H, m-C₅H₄R), 4.06 (m, 1 H, m-C₅H₄R), 4.93 (m, 1 H, o-

3

4

C₅H₄R), 5.13 (dd, J ϭ 2.8 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 5.16

(m, 1 H, PCH), 6.90 (m, 3 H), 7.10 (m, 3 H, m/p-C₆H₅), 7.76 (m,

4

2 H, o-C₆H₅), 8.31 (ddd, J ϭ 9.6 Hz, J ϭ 8.2 Hz, J ϭ 1.4 Hz, 2

2

SAMP-hydrazone 3b: According to GP3A, a solution of LDA (1.2

equiv.) and LiClO₄(3.6 equiv.) in diethyl ether (2 mL) was treated

with a solution of hydrazone 2d (178 mg, 0.428 mmol) in diethyl

ether (5 mL). After cooling to Ϫ100 °C, methyl iodide was added

(40 µL, 1.5 equiv.). Aqueous work up and purification by filtration

through silica gel (hexane/diethyl ether ϭ 4:1; 2% NEt₃) provided

H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 16.3 (d, J_CP

ϭ

1

4.5 Hz, CH₃), 23.4 (NCH₂CH₂), 27.9 (NCHCH₂), 34.0 (d, J_CP

ϭ

28.0 Hz, PCH), 57.0 (NCH₂), 59.4 (OCH₃), 68.0, 68.4, 70.0, 70.1,

71.2 (NCH, C₅H₄R), 70.5 (C₅H₅), 76.5 (OCH₂), 82.2 (i-C₅H₄R),

3

4

129.5 (d, J_CPϭ 9.7 Hz, m-C₆H₅), 131.5 (d, J_CPϭ 2.2 Hz), 131.8

4

2

(d, J_CPϭ 2.2 Hz, p-C₆H₅), 134.3 (d, J_CPϭ 9.2 Hz), 134.4 (d,

hydrazone 3b. Ϫ Yield: 175 mg (95%, red oil). Ϫ R_fϭ 0.33 (hexane/ ²J_CPϭ 8.5 Hz, o-C₆H₅), 164.8 (CϭN). Ϫ ³¹P NMR (121 MHz,

diethyl ether ϭ 4:1; 2% NEt₃). Ϫ (E)/(Z) Ն 100:1. Ϫ de ϭ 48% (¹H C₆D₆): δ ϭ ϩ24.8 (broad). Ϫ EI-MS; m/z: 538.2 (24) [M^ϩϪ BH₃],

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3409

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

424.1 (24) [538.2 Ϫ C₆H₁₂NO], 354.2 (17), 353.1 (56) [538.2 Ϫ SCH₃), 1.98 (m, 1 H, β-ring-CH₂), 2.42 (dt, ²J ϭ 8.5 Hz, ³J ϭ

PPh₂], 239.9 (70), 213.1 (14), 212.2 (11), 210.9 (35) [FcCN^ϩ], 186.1

8.2 Hz, 1 H, NCH₂), 2.91 (ddd, ²J ϭ 9.1 Hz, ³J ϭ 7.4 Hz, ³J ϭ

(17) [Cp₂Fe^ϩ], 184.9 (100) [PPh₂or Fc^ϩ], 183.0 (51), 147.1 (67),

4.1 Hz, 1 H, NCH₂), 3.13 (s, 3 H, OCH₃), 3.25 (dd, J ϭ 8.8 Hz,

ϩ

2

128.9 (35) [C₁₀H₉^ϩ], 120.9 (50) [CpFe^ϩ], 109.1 (11) [PhPH^ϩ], 108.1

³J ϭ 6.9 Hz, 1 H, OCH₂), 3.51 (dd, ²J ϭ 8.8 Hz, ³J ϭ 4.1 Hz, 1

(10) [PhP^ϩ], 58.3 (13), 56.3 (16) [Fe^ϩ], 45.3 (30) [CH₂OCH₃^ϩ]. Ϫ H, OCH₂), 3.58 (qd, J ϭ 7.4 Hz, J ϭ 4.1 Hz, 1 H, NCH), 4.09

3

HR-MS: C₃₁H₃₈B⁵⁶FeN₂OP (M^ϩϪ BH₃) calcd. 538.183649; found (s, 5 H, C₅H₅), 4.14 (m, 2 H, m-C₅H₄R), 4.92 (q, J ϭ 7.7 Hz, 1

3

4

538.183591. Ϫ C₃₁H₃₈BFeN₂OP (552.3): calcd. C 60.00, H 7.05, N

7.00; found C 60.17, H 7.22; N 6.85.

H, SCH), 4.97 (dt, J ϭ 2.4 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 5.27

(dt, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R). Ϫ ¹³C NMR

(75 MHz, C₆D₆): δ ϭ 15.3, 19.2 (CH₃), 22.5 (NCH₂CH₂), 27.3

(NCHCH₂), 39.2 (SCH), 56.2 (NCH₂), 58.7 (OCH₃), 67.1, 67.8,

69.1, 69.3, 70.8 (NCH, C₅H₄R), 69.9 (C₅H₅), 76.2 (OCH₂), 80.2 (i-

C₅H₄R), 165.9 (CϭN). Ϫ EI-MS; m/z: 400.1 (95) [M^ϩ], 352.9 (11)

[M^ϩϪ CH₃S], 308.1 (12) [M^ϩϪ CH₃OCH₂SCH₃], 307.0 (55),

286.0 (17) [M^ϩϪ C₆H₁₂NO], 241.1 (12), 240.0 (30) [286.0 Ϫ

CH₃OCH₃], 239.1 (12), 237.9 (16) [286.0 Ϫ H₃CSH], 230.1 (12),

213.0 (22), 212.1 (28), 210.9 (78) [FcCN^ϩ], 187.1 (20), 186.0 (13)

[Cp₂Fe^ϩ], 184.9 (57) [Fc^ϩ], 142.1 (46), 129.1 (19) [C₁₀H₉^ϩ], 91.1

(33), 75.0 (100) [H₃CSCHCH₃^ϩ], 55.9 (17) [Fe^ϩ]. Ϫ C₂₀H₂₈FeN₂OS

(400.4): calcd. C 60.00, H 7.05, N 7.00; found C 60.17, H 7.22,

N 6.85.

SAMP-hydrazone 3d: According to GP3B, a solution of LDA (1.1

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (10 mL) was treated

with a solution of hydrazone 2b (1.52 g, 4.13 mmol) in diethyl ether

(16 mL). After cooling to Ϫ100 °C, a solution of Ph₂PCl·BH₃(1.2

equiv.) in diethyl ether (2 mL) was added dropwise. Aqueous work

up, purification by filtration through silica gel (hexane/diethyl

ether ϭ 4:1) and crystallization from hexane at Ϫ26 °C provided

hydrazone 3d. Ϫ Yield: 2.27 g (97%, red crystals). Ϫ (E)/(Z) ϭ 44:1.

Ϫ R_fϭ 0.20 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵

ϭ

Ϫ79.2 (CHCl₃, c ϭ 0.53). Ϫ M.p.: 92 °C. Ϫ IR (KBr): ν˜ ϭ 3096

cm^Ϫ1, 3053, 2967, 2925, 2874, 2826, 2401, 2276, 1620, 1563, 1455,

1437, 1411, 1383, 1333, 1290, 1246, 1197, 1105, 1063, 1000, 972,

894, 815, 741, 700, 639, 607, 559, 499, 471. Ϫ ¹H NMR [(E) isomer, SAMP-hydrazone 3f: According to GP3A, a solution of LDA (1.2

3

300 MHz, C₆D₆]: δ ϭ 0.99 (t, J ϭ 7.4 Hz, 3 H, CH₃), 1.53Ϫ1.90

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (20 mL) was treated

(m, 6 H, β-ring-CH₂, BH₃), 1.95Ϫ2.33 (m, 3 H, β-ring-CH₂, with a solution of hydrazone 2b (3.74 g, 10.1 mmol) in diethyl ether

CH₂CH₃), 2.43 (q, ^2/3J ϭ 8.4 Hz, 1 H, NCH₂), 2.77 (m, 1 H, (20 mL). After cooling to Ϫ100 °C, dimethyl disulfide (1.19 mL,

NCH₂), 3.13 (s, 3 H, OCH₃), 3.16Ϫ3.27 (m, 2 H, OCH₂), 3.46 (m, 1.3 equiv.) was added dropwise. Aqueous work up and purification

1 H, NCH), 3.94 (s, 5 H, C₅H₅), 3.98 (td, ³J ϭ 2.4 Hz, ⁴J ϭ 1.0 Hz, by filtration through silica gel (hexane/diethyl ether ϭ 4:1) provided

1 H, m-C₅H₄R), 4.08 (td, ³J ϭ 2.4 Hz, ⁴J ϭ 1.3 Hz, 1 H, m-

hydrazone 3f. Ϫ Yield: 3.91 g (93%, orange-red crystals). Ϫ R_fϭ

C₅H₄R), 4.78 (dt, J ϭ 2.7 Hz, J ϭ 1.3 Hz, 1 H, o-C₅H₄R), 5.08 0.29 (hexane/diethyl ether ϭ 4:1). Ϫ (E)/(Z) ϭ 28:1. Ϫ de Ն 96%.

3

4

1

3

(ddd, J_CPϭ 14.1 Hz, J ϭ 9.4 Hz, J ϭ 4.7 Hz, PCH), 5.14 (dt,

Ϫ [α]²_D⁵ϭ ϩ257.8 (CHCl₃, c ϭ 0.79). Ϫ M.p.: 90 °C. Ϫ IR (KBr):

³J ϭ 2.4 Hz, ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 6.88 (m, 3 H), 7.08Ϫ7.20 ν˜ ϭ 3110 cm^Ϫ1, 2961, 2915, 2871, 2808, 2727, 2279, 2238, 2056,

(m, 3 H, m/p-C₆H₅), 7.72 (m, 2 H), 8.50 (m, 2 H, o-C₆H₅). Ϫ ¹³C 1777, 1705, 1669, 1560, 1444, 1382, 1349, 1333, 1298, 1279, 1255,

3

NMR [(E) isomer, 75 MHz, C₆D₆): δ ϭ 15.4 (d, J_CPϭ 4.2 Hz,

CH₃), 22.8 (NCH₂CH₂), 34.4 (d, J_CPϭ 4.9 Hz, CH₂CH₃), 27.1 662, 594, 577, 519, 493, 455. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ

1235, 1195, 1108, 1042, 1002, 962, 911, 883, 821, 757, 720, 686,

2

1

3

(NCHCH₂), 40.8 (d, J_CPϭ 26.2 Hz, PCH), 56.7 (NCH₂), 58.8 1.06 (t, J ϭ 7.4 Hz, 3 H, CH₃), 1.57Ϫ2.05 (m, 6 H, CH₂CH₃, β-

(OCH₃), 67.5, 68.4, 68.9, 69.3, 70.6 (NCH, C₅H₄R), 70.0 (C₅H₅), ring-CH₂), 2.00 (s, 3 H, SCH₃), 2.46 (dt, ²J ϭ 10.4 Hz, ³J ϭ 8.8 Hz,

3

2

3

75.4 (OCH₂), 82.2 (i-C₅H₄R), 127.8 (d, J_CPϭ 10.4 Hz), 128.8 (d,

1 H, NCH₂), 2.96 (ddd, J ϭ 9.1 Hz, J ϭ 8.4 Hz, J ϭ 4.4 Hz, 1

³J_CPϭ 9.7 Hz, m-C₆H₅), 129.4 (d, J_CPϭ 52.5 Hz), 132.3 (d, H, NCH₂), 3.15 (s, 3 H, OCH₃), 3.28 (dd, ²J ϭ 10.2 Hz, ³J ϭ

1

¹J_CPϭ 53.1 Hz, i-C₆H₅), 130.5 (d, ⁴J_CPϭ 2.5 Hz), 131.1 (d, ⁴J_CPϭ

8.2 Hz, 1 H, OCH₂), 3.52 (dd, ²J ϭ 10.2 Hz, ³J ϭ 4.1 Hz, 1 H,

2.4 Hz, p-C₆H₅), 133.8 (d, ²J_CPϭ 6.7 Hz), 133.9 (d, ²J_CPϭ 6.1 Hz, OCH₂), 3.54 (m, 1 H, NCH), 4.15 (s, 5 H, C₅H₅), 4.16 (m, 1 H, m-

o-C₆H₅), 164.6 (CϭN). Ϫ ³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ23.2 C₅H₄R), 4.18 (td, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, m-C₅H₄R), 4.65

3

4

(broad). Ϫ EI-MS; m/z: 552.3 (9) [M^ϩϪ BH₃], 452.0 (42) [M^ϩ

Ϫ

(dd, J ϭ 9.6 Hz, J ϭ 5.8 Hz, 1 H, SCH), 4.89 (dt, J ϭ 2.5 Hz,

3

C₆H₁₂NO], 438.1 (21) [452.0 Ϫ BH₃], 367.1 (64) [M^ϩϪ Ph₂P Ϫ ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 5.17 (dt, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1

3

4

BH₃], 253.9 (73) [452.0 Ϫ Ph₂P Ϫ BH₂], 252.0 (53) [438.1 Ϫ

H, o-C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.4, 15.5 (CH₃),

22.5 (NCH₂CH₂), 26.8, 27.3 (CH₂CH₃, NCHCH₂), 47.1 (SCH),

Ph₂PH], 227.0 (32), 211.0 (32) [FcCN^ϩ], 186.2 (27) [CpFe^ϩor

Ph₂PH^ϩ], 185.0 (100) [Fc^ϩor Ph₂P^ϩ], 183.1 (44) [185.0 Ϫ H₂], 56.4 (NCH₂), 58.7 (OCH₃), 67.3, 68.1, 69.06, 69.11, 71.1 (NCH,

156.2 (55), 129.0 (28) [C₁₀H₉^ϩ], 121.0 (36) [CpFe^ϩ], 108.2 (13) C₅H₄R), 70.0 (C₅H₅), 76.1 (OCH₂), 80.9 (i-C₅H₄R), 166.2 (CϭN).

[C₆H₅P^ϩ]. Ϫ C₃₂H₄₀BFeN₂OP (566.3): calcd. C 67.87, H 7.12, N

4.95; found C 67.70, H 7.05, N 4.64.

Ϫ EI-MS; m/z: 414.2 (100) [M^ϩ], 367.1 (16) [M^ϩϪ CH₃S], 321.1

(51), 299.9 (25) [M^ϩϪ C₆H₁₂NO], 254.1 (23), 253.2 (25), 252.0

(52) [299.9 Ϫ CH₃SH], 227.0 (19), 212.2 (19), 211.0 (56) [FcCN^ϩ],

201.0 (12), 186.1 (11) [Cp₂Fe^ϩ], 184.9 (45) [Fc^ϩ], 156.1 (27), 128.9

(18) [C₁₀H₉^ϩ], 121.0 (42) [CpFe^ϩ], 90.9 (14), 89.1 (56)

[H₃CSCHCH₂CH₃^ϩ]. Ϫ C₂₁H₃₀FeN₂OS (414.4): calcd. C 60.87, H

7.30, N 6.76; found C 61.10, H 7.50, N 6.56.

SAMP-hydrazone 3e: According to GP3A, a solution of LDA (1.2

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (5 mL) was treated

with a solution of hydrazone 2a (669 mg, 1.82 mmol) in diethyl

ether (5 mL). After cooling to Ϫ100 °C, dimethyl disulfide

(0.29 mL, 1.7 equiv.) was added dropwise. Aqueous work up and

purification by filtration through silica gel (hexane/diethyl ether ϭ

4:1) provided hydrazone 3e. Ϫ Yield: 690 mg (95%, orange-red

SAMP-hydrazone 3g: According to GP3A, a solution of LDA (1.2

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (20 mL) was treated

crystals). Ϫ R_fϭ 0.50 (hexane/diethyl ether ϭ 4:1). Ϫ (E)/(Z) ϭ with a solution of hydrazone 2a (3.34 g, 9.44 mmol) in diethyl ether

12:1. Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ270.9 (CHCl₃, c ϭ 0.62). Ϫ M.p.:

86 °C. Ϫ IR (KBr): ν˜ ϭ 3106 cm^Ϫ1, 2971, 2918, 2873, 2734, 2226,

(15 mL). After cooling to Ϫ100 °C, diisopropyl disulfide (2.26 mL,

1.5 equiv.) was added dropwise. Aqueous work up and purification

2053, 1672, 1639, 1559, 1454, 1378, 1343, 1323, 1297, 1248, 1185, by filtration through silica gel (hexane/diethyl ether ϭ 4:1) provided

1107, 1049, 1028, 999, 956, 884, 817, 762, 716, 688, 670, 630, 594, hydrazone 3g. Ϫ Yield: 3.74 g (92%, orange-brown crystals). Ϫ

534, 481. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 1.55 (d, ³J ϭ 7.4 Hz, R_fϭ 0.48 (Hex/Et₂O ϭ 4:1). Ϫ (E)/(Z) ϭ 50:1. Ϫ de Ն 96%. Ϫ

3 H, CHCH₃), 1.58Ϫ1.77 (m, 3 H, β-ring-CH₂), 1.92 (s, 3 H, [α]²_D⁵ϭ ϩ245.7 (CHCl₃, c ϭ 0.60). Ϫ M.p.: 82 °C. Ϫ IR (KBr):

3410

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

ν˜ ϭ 3113 cm^Ϫ1, 3096, 3082, 2966, 2926, 2888, 2870, 2827, 2809, solution was cooled to 0 °C and treated with 1.7 equiv. BH₃DMS

2731, 2371, 2248, 2057, 1786, 1737, 1719, 1701, 1686, 1655, 1565, for 3 h. Aqueous work up and purification by filtration through

1459, 1410, 1379, 1365, 1352, 1337, 1297, 1282, 1253, 1196, 1154, silica gel (hexane/diethyl ether ϭ 7:1) provided hydrazone 3i. Ϫ

1121, 1104, 1045, 1028, 1001, 964, 910, 881, 836, 819, 770, 738, Yield: 568 mg (96%, orange oil). Ϫ R_fϭ 0.48 (hexane/diethyl

692, 651, 630, 596, 548, 519, 482. Ϫ H NMR (300 MHz, C₆D₆): ether ϭ 4:1). Ϫ (E)/(Z) ϭ 9:1. Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ120.5

1

3

δ ϭ 1.15 [d, J ϭ 6.9 Hz, 3 H, CH(CH₃)₂], 1.33 [d, J ϭ 6.6 Hz, 3 (CHCl₃, c ϭ 0.52). Ϫ IR (neat): ν˜ ϭ 3096 cm^Ϫ1, 2964, 2934, 2874,

H, CH(CH₃)₂], 1.55Ϫ1.73 (m, 3 H, β-ring-CH₂), 1.60 (d, ³J ϭ

2827, 2733, 2379, 2277, 1673, 1563, 1462, 1415, 1384, 1353, 1338,

7.7 Hz, 3 H, NϭCCHCH₃), 2.01 (m, 1 H, β-ring-CH₂), 2.42 (dt, 1249, 1199, 1185, 1107, 1055, 1002, 970, 932, 884, 821, 753, 684,

3

²J ϭ 8.8 Hz, J ϭ 8.0 Hz, 1 H, NCH₂), 2.88 [sept, J ϭ 6.6 Hz, 1 651, 597, 495. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 0.92 (dd, ³J_HPϭ

H, CH(CH₃)₂], 3.01 (ddd, J ϭ 8.8 Hz, J ϭ 7.4 Hz, J ϭ 4.1 Hz, 13.2 Hz, ³J ϭ 6.8 Hz, 3 H), 1.05 (dd, ³J_HPϭ 15.4 Hz, ³J ϭ 7.1 Hz,

2

3

1 H, NCH₂), 3.18 (s, 3 H, OCH₃), 3.32 (dd, ²J ϭ 8.5 Hz, ³J ϭ 3 H), 1.13 (dd, ³J_HPϭ 12.6 Hz, ³J ϭ 6.9 Hz, 3 H), 1.20 [dd, ³J_HPϭ

7.2 Hz, 1 H, OCH₂), 3.60 (dd, ²J ϭ 8.5 Hz, ³J ϭ 4.4 Hz, 1 H,

13.7 Hz, ³J ϭ 7.1 Hz, 3 H, PCH(CH₃)₂], 1.54Ϫ1.98 (m, 5 H, β-

3

OCH₂), 3.63 (qd, J ϭ 7.7 Hz, J ϭ 4.4 Hz, 1 H, NCH), 4.09 (s, 5

ring-CH₂, NCH₂), 1.73 (dd, ²J_HPϭ 14.5 Hz, ³J ϭ 7.7 Hz, 3 H, Nϭ

H, C₅H₅), 4.14 (m, 2 H, m-C₅H₄R), 4.94 (q, ³J ϭ 7.4 Hz, 1 H, Nϭ CCHCH₃), 2.05 [dsept, J_HPϭ 12.4 Hz, ³J ϭ 7.1 Hz, 1 H,

2

CCHCH₃), 4.98 (dt, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 5.24

CH(CH₃)₂], 2.39 [dsept, J_HPϭ 16.7 Hz, ³J ϭ 7.1 Hz, 1 H,

2

(dt, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R). Ϫ ¹³C NMR CH(CH₃)₂], 3.04 (ddd, ²J ϭ 9.3 Hz, ³J ϭ 6.9 Hz, ³J ϭ 4.1 Hz, 1

(75 MHz, C₆D₆): δ ϭ 20.4, 23.5, 24.8 (CH₃), 22.7 (NCH₂CH₂),

H, NCH₂), 3.08 (s, 3 H, OCH₃), 3.25 (dd, ²J ϭ 9.3 Hz, ³J ϭ 6.3 Hz,

27.6 (NCHCH₂), 35.9, 36.8 (SCH), 56.5 (NCH₂), 58.9 (OCH₃), 1 H, OCH₂), 3.37 (dd, ²J ϭ 9.1 Hz, ³J ϭ 4.1 Hz, 1 H, OCH₂), 3.50

3

4

67.3, 67.9, 69.2, 69.3, 71.0 (NCH, C₅H₄R), 70.1 (C₅H₅), 76.6

(m, 1 H, NCH), 3.98 (s, 5 H, C₅H₅), 4.10 (td, J ϭ 2.5 Hz, J ϭ

3

4

(OCH₂), 80.6 (i-C₅H₄R), 165.5 (CϭN). Ϫ EI-MS; m/z: 429.0 (81) 1.1 Hz, 1 H, m-C₅H₄R), 4.16 (td, J ϭ 2.5 Hz, J ϭ 1.7 Hz, 1 H,

[MH^ϩ], 428.1 (100) [M^ϩ], 353.1 (12) [M^ϩϪ SCH(CH₃)₂]. Ϫ m-C₅H₄R), 4.23 (dq, ²J_HPϭ 16.8 Hz, ³J ϭ 7.2 Hz, 1 H, NϭCCH),

C₂₂H₃₂FeN₂OS (428.4): calcd. C 61.68, H 7.53, N 6.54; found C 5.20 (m, 2 H, o-C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 18.0

2

61.74, H 7.66, N 6.38.

(d, J_CPϭ 2.3 Hz), 18.9 [d, J_CPϭ 1.1 Hz, CH(CH₃)₂], 18.3 (Nϭ

1

CCHCH₃), 21.7 (d, J_CPϭ 29.8 Hz), 25.2 [d, J_CPϭ 30.9 Hz,

CH(CH₃)₂], 22.6 (NCH₂CH₂), 26.5 (NCHCH₂), 27.8 (d, J_CP

1

SAMP-hydrazone 3h: According to GP3A, a solution of LDA (1.1

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (4 mL) was treated

with a solution of hydrazone 2b (530 mg, 1.44 mmol) in diethyl

ether (3 mL). After cooling to Ϫ100 °C, diisopropyl disulfide

(0.32 mL, 1.4 equiv.) was added dropwise. Aqueous work up and

purification by filtration through silica gel (hexane/diethyl ether ϭ

4:1) provided hydrazone 3h. Ϫ Yield: 616 mg (97%, orange-red

crystals). Ϫ R_fϭ 0.59 (hexane/diethyl ether ϭ 4:1). Ϫ (E)/(Z) ϭ

9:1. Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ327.8 (CHCl₃, c ϭ 1.17). Ϫ M.p.: 81

°C. Ϫ IR (KBr): ν˜ ϭ 3102 cm^Ϫ1, 3084, 2961, 2926, 2869, 2824,

2731, 2248, 1673, 1640, 1566, 1455, 1411, 1381, 1331, 1299, 1250,

1199, 1182, 1156, 1106, 1052, 1024, 1000, 955, 922, 890, 822, 742,

ϭ

22.3 Hz, NϭCCH), 56.1 (NCH₂), 58.7 (OCH₃), 67.0, 67.6, 69.66,

69.72, 71.4 (NCH, C₅H₄R), 69.9 (C₅H₅), 75.3 (OCH₂), 82.6 (i-

C₅H₄R), 164.4 (CϭN). Ϫ ³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ43.8

(broad). Ϫ EI-MS; (75 MHz, C₆D₆): δ ϭ 484.3 (2) [M^ϩ], 427.1 (20)

[M^ϩϪ BH₃Ϫ (H₃C)₂CH], 370.1 (100) [M^ϩϪ C₆H₁₂NO], 241.1

(11), 210.9 (14) [FcCN^ϩ], 184.9 (21) [Fc^ϩ], 121.0 (25) [CpFe^ϩ], 70.2

(12). Ϫ CI-MS (isobutane); m/z: 485.2 (43) [MH^ϩ], 484.2 (45) [M^ϩ],

483.2 (100) [M^ϩϪ H], 482.2 (42) [M^ϩϪ H₂], 370.1 (34) [M^ϩ

Ϫ

C₆H₁₂NO], 369.1 (19) [M^ϩϪ C₆H₁₃NO], 119.1 (15), 116.0 (17),

114.1 (12). Ϫ C₂₅H₄₂BFeN₂OP (485.3): calcd. C 62.01, H 8.74, N

5.78; found C 62.18, H 8.67, N 6.27.

1

684, 670, 649, 628, 553, 488. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ

1.10 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.20 (d, ³J ϭ 6.8 Hz, 3 H,

SAMP-hydrazone 3j: According to GP3A, a solution of LDA (1.2

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (8 mL) was treated

with a solution of hydrazone 2c (2.01 g, 5.26 mmol) in diethyl ether

(8 mL). After cooling to Ϫ100 °C, a solution of di-p-tolyl disulfide

(1.94 g, 1.5 equiv.) in diethyl ether (6 mL) was added dropwise.

Aqueous work up and purification by flash chromatography

through silica gel (hexane/diethyl ether ϭ 4:1) provided hydrazone

3j. Ϫ Yield: 2.33 g (88%, red oil). Ϫ R_fϭ 0.50 (hexane/diethyl

ether ϭ 4:1). Ϫ (Z)/(E) Ն 100:1. Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ677.9

(CHCl₃, c ϭ 1.07). Ϫ IR (neat): ν˜ ϭ 3095 cm^Ϫ1, 3017, 2962, 2922,

2870, 2829, 2732, 1670, 1580, 1493, 1460, 1412, 1398, 1383, 1365,

1352, 1334, 1292, 1240, 1199, 1184, 1165, 1121, 1107, 1046, 1019,

1002, 970, 940, 916, 893, 812, 633, 496. Ϫ ¹H NMR (300 MHz,

3

CHCH₃), 1.33 (d, J ϭ 6.6 Hz, 3 H, CHCH₃), 1.52Ϫ2.07 (m, 6 H,

CH₂CH₃, β-ring-CH₂), 2.45 (td, ^2/3J ϭ 8.8 Hz, J ϭ 7.7 Hz, 1 H,

3

NCH₂), 2.96 [sept, ³J ϭ 6.6 Hz, 1 H, CH(CH₃)₂], 3.02 (m, 1 H,

2

3

NCH₂), 3.18 (s, 3 H, OCH₃), 3.33 (dd, J ϭ 9.9 Hz, J ϭ 8.2 Hz,

1 H, OCH₂), 3.59 (dd, ²J ϭ 10.2 Hz, ³J ϭ 4.1 Hz, 1 H, OCH₂),

3.59 (m, 1 H, NCH), 4.14 (s, 5 H, C₅H₅), 4.15 (m, 2 H, m-C₅H₄R),

4.58 (dd, ³J ϭ 10.4 Hz, ³J ϭ 5.0 Hz, 1 H, NϭCCHS), 4.89 (t, ³J ϭ

4

3

4

2.5 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 5.15 (dt, J ϭ 2.5 Hz, J ϭ

1.3 Hz, 1 H, o-C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.4,

23.6, 24.6 (CH₃), 22.6 (NCH₂CH₂), 27.3, 27.4 (CH₂CH₃,

NCHCH₂), 35.8, 44.4 (SCH), 56.3 (NCH₂), 58.7 (OCH₃), 67.2,

68.1, 68.9, 69.0, 71.1 (NCH, C₅H₄R), 70.0 (C₅H₅), 76.4 (OCH₂),

81.1 (i-C₅H₄R), 166.8 (CϭN). Ϫ EI-MS; m/z: 442.1 (100) [M^ϩ],

367.1 (18) [M^ϩϪ (H₃C)₂CHS], 327.9 (22) [M^ϩϪ C₆H₁₂NO], 321.0

(40), 285.9 (27), 255.1 (17), 254.0 (35), 253.1 (48), 251.9 (62), 226.9

(19), 212.0 (18), 210.9 (45) [FcCN^ϩ], 201.1 (16), 186.0 (12)

[Cp₂Fe^ϩ], 184.9 (45) [Fc^ϩ], 156.1 (29), 128.9 (16) [C₁₀H₉^ϩ], 120.9

(41) [CpFe^ϩ], 117.0 (44) [(H₃C)₂CHSϪCHϪCH₂CH₃^ϩ], 75.0 (23)

[(H₃C)₂CHS^ϩ]. Ϫ C₂₃H₃₄FeN₂OS (442.4): calcd. C 62.44, H 7.75,

N 6.33; found C 62.49, H 7.82, N 5.98.

3

C₆D₆): δ ϭ 0.82 [broad d, J ϭ 6.4 Hz, 3 H, CH(CH₃)₂], 1.19 [d,

³J ϭ 6.7 Hz, 3 H, CH(CH₃)₂], 1.55Ϫ2.85 (m, 3 H, β-ring-CH₂),

2.06 (s, 3 H, C₆H₄CH₃), 2.10 [m, 1 H, CH(CH₃)₂], 2.26 (m, 1 H,

β-ring-CH₂), 2.55 (m, 1 H, NCH₂), 3.04 (m, 1 H, NCH₂), 3.16 (s,

3 H, OCH₃), 3.17 (m, 1 H, OCH₂), 3.51 (m, 1 H, NCH), 3.56 (dd,

3

4

²J ϭ8.7 Hz, J ϭ 4.0 Hz, 1 H, OCH₂), 4.13 (td, J ϭ 2.7 Hz, J ϭ

1.3 Hz, 1 H, m-C₅H₄R), 4.15 (t, ^3/4J ϭ 2.0 Hz, 1 H, m-C₅H₄R),

4.26 (s, 5 H, C₅H₅), 4.92 (broad s, 1 H, o-C₅H₄R), 5.01 (broad d,

³J ϭ 8.7 Hz, 1 H, SCH), 5.10 (broad s, 1 H, o-C₅H₄R), 6.95 (d,

3

SAMP-hydrazone 3i: According to GP3B, a solution of LDA (1.2

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (4 mL) was treated

with a solution of hydrazone 2a (433 mg, 1.22 mmol) in diethyl

ether (4 mL). After cooling to Ϫ100 °C, iPr₂PCl (1.4 equiv.) was

added dropwise. After warming to room temperature overnight, the

³J ϭ 7.7 Hz, 2 H, C₆H₄), 7.69 (d, J ϭ 7.7 Hz, 2 H, C₆H₄). Ϫ ¹³C

NMR (75 MHz, C₆D₆):

δ ϭ 20.9, 21.6, 21.8 (CH₃), 22.5

(NCH₂CH₂), 27.8 (NCHCH₂), 33.4 [CH(CH₃)₂], 54.3 (SCH), 55.9

(NCH₂), 58.9 (OCH₃), 67.5, 68.9, 69.0, 69.3, 71.0 (NCH, C₅H₄R),

70.6 (C₅H₅), 76.1 (OCH₂), 129.9, 131.1 (C₆H₄), 168.5 (CϭN). Ϫ

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3411

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

Ϫ

HSCH₃], 251.1 (11), 215.2 (21), 212.2 (30) [FcCNH^ϩ], 211.1 (64)

FULL PAPER

EI-MS; m/z: 505.1 (100) [MH^ϩ], 504.1 (99) [M^ϩ].

C₂₈H₃₆FeN₂OS (504.5): calcd. C 66.66, H 7.19, N 5.55; found C [FcCN^ϩ], 186.1 (17) [Cp₂Fe^ϩ], 185.0 (58) [Fc^ϩ], 170.2 (34), 167.7

66.59, H 7.36, N 5.53.

(16), 129.1 (33) [C₁₀H₉^ϩ], 128.1 (19) [C₁₀H₈^ϩ], 121.0 (75) [CpFe^ϩ],

103.1 (93) [H₃CSCHCH(CH₃)₂^ϩ], 56.1 (16) [Fe^ϩ], 55.2 (45), 45.3

(22) [H₃COCH₂^ϩ]. Ϫ C₂₂H₃₂FeN₂OS (428.4): calcd. C 61.68, H

7.53, N 6.54; found C 61.84, H 7.54, N 6.37.

SAMP-hydrazone 3k: According to GP3A, a solution of LDA (1.2

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (3 mL) was treated

with a solution of hydrazone 2c (170 mg, 0.445 mmol) in diethyl

ether (3 mL). After cooling to Ϫ100 °C, methyl iodide (41 µL, 1.4

equiv.) was added dropwise. Aqueous work up and purification by

filtration through silica gel (hexane/diethyl ether ϭ 4:1) provided

hydrazone 3k. Ϫ Yield: 168 mg (95%, red-brown oil). Ϫ R_fϭ 0.40

SAMP-hydrazone 3m: According to GP3A, a solution of LDA (1.1

equiv.) and LiClO₄(3.3 equiv.) in diethyl ether (5 mL) was treated

with a solution of hydrazone 2c (500 mg, 1.36 mmol) in diethyl

ether (6 mL). After cooling to Ϫ100 °C, a solution of di-p-tolyl

(hexane/diethyl ether ϭ 4:1). Ϫ (Z)/(E) Ն 50:1. Ϫ de Ն 96%. Ϫ ¹H disulfide (435 mg, 1.3 equiv.) in diethyl ether (1 mL) was added

NMR (300 MHz, C₆D₆): δ ϭ 0.81 [d, ³J ϭ 6.7 Hz, 3 H, CH(CH₃)₂],

dropwise. Aqueous work up and purification by flash chromato-

0.93 [d, J ϭ 6.4 Hz, 3 H, CH(CH₃)₂], 1.30 (d, J ϭ 7.1 Hz, 3 H, graphy through silica gel (hexane/ethyl acetate ϭ 10:1; 2% NEt₃)

3

NϭCCHCH₃), 1.60Ϫ2.11 (m, 6 H, β-ring-CH₂, CHCH), 2.65 (dt,

provided hydrazone 3m. Ϫ Yield: 659 mg (99%, orange crystals).

²J ϭ 9.1 Hz, ³J ϭ 8.7 Hz, 1 H, NCH₂), 3.00 (dd, ²J ϭ 9.4 Hz, ³J ϭ Ϫ R_fϭ 0.38 (hexane/diethyl ether ϭ 4:1; 2% NEt₃). Ϫ (E)/(Z) ϭ

3

7.4 Hz, J ϭ 3.4 Hz, 1 H, NCH₂), 3.23 (s, 3 H, OCH₃), 3.38 (dd,

5:1. Ϫ de Ն 96%. Ϫ M.p.: 85 °C. Ϫ IR (KBr): ν˜ ϭ 3093 cm^Ϫ1

,

²J ϭ 9.1 Hz, ³J ϭ 4.0 Hz, 1 H, OCH₂), 3.52 (dd, ²J ϭ 9.1 Hz, ³J ϭ 3083, 3034, 3019, 2966, 2925, 2871, 2847, 2822, 2810, 2732, 2242,

3

7.4 Hz, 1 H, OCH₂), 3.56 (m, 1 H, NCH), 4.10 (td, J ϭ 2.4 Hz,

1764, 1719, 1687, 1655, 1637, 1599, 1569, 1495, 1477, 1458, 1409,

3

4

⁴J ϭ 1.4 Hz, 1 H, m-C₅H₄R), 4.13 (td, J ϭ 2.7 Hz, J ϭ 1.3 Hz, 1382, 1350, 1336, 1298, 1275, 1253, 1213, 1198, 1182, 1127, 1105,

3

4

1 H, m-C₅H₄R), 4.15 (s, 5 H, C₅H₅), 4.50 (dt, J ϭ 2.4 Hz, J ϭ 1096, 1096, 1074, 1050, 1022, 1000, 971, 935, 913, 886, 820, 804.

1.3 Hz, 1 H, o-C₅H₄R), 5.02 (dt, ³J ϭ 2.7 Hz, ⁴J ϭ 1.3 Hz, 1 H, o-

C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 17.7, 21.2, 22.3 (CH₃),

22.2 (NCH₂CH₂), 27.5 (NCHCH₂), 31.0 [CH(CH₃)₂], 42.2 (Nϭ

Ϫ

¹H NMR (major isomer, 300 MHz, C₆D₆): δ ϭ 0.84 (t, ³J ϭ

7.4 Hz, 3 H, CH₂CH₃), 1.58Ϫ1.76 (m, 3 H, β-ring-CH₂), 1.88Ϫ2.15

(m, 3 H, CH₂CH₃, β-ring-CH₂), 2.06 (s, 3 H, C₆H₄CH₃), 2.86 (q,

CCH), 55.9 (NCH₂), 58.8 (OCH₃), 66.8, 68.6, 68.8, 69.1, 70.0 ³J ϭ 7.3 Hz, 1 H, NCH₂), 3.14 (s, 3 H, OCH₃), 3.13Ϫ3.57 (m, 4

(NCH, C₅H₄R), 69.9 (C₅H₅), 76.4 (OCH₂), 82.1 (i-C₅H₄R), 174.2 H, OCH₂, NCH, NCH₂), 4.20 (m, 2 H, m-C₅H₄R), 4.26 (s, 5 H,

(CϭN). Ϫ EI-MS; m/z: 396.3 (55) [M^ϩ], 351.3 (31) [M^ϩ

CH₂OCH₃], 331.3 (18) [M^ϩϪ C₅H₅], 282.1 (100) [M^ϩ

Ϫ

C₅H₅), 5.06 (dt, ³J ϭ 2.5 Hz, ⁴J ϭ 1.1 Hz, 1 H, o-C₅H₄R), 5.23 (m,

1 H, o-C₅H₄R), 5.32 (m, 1 H, SCH), 6.91 (d, ³J ϭ 8.0 Hz, 2 H,

Ϫ

C₆H₁₂NO], 211.0 (52) [FcCN^ϩ], 186.1 (18) [Cp₂Fe^ϩ], 185.0 (68) C₆H₄), 7.50 (d, J ϭ 8.0 Hz, 2 H, C₆H₄). Ϫ H NMR (minor iso-

3

1

[Fc^ϩ], 175.4 (20), 129.1 (41) [C₁₀H₉^ϩ], 122.0 (12) [C₅H₆Fe^ϩ], 121.0

(96) [CpFe^ϩ], 83.1 (14), 77.2 (14), 71.2 (44) [H₃CCHCH(CH₃)₂^ϩ], 1.52Ϫ1.80 (m, 3 H, β-ring-CH₂), 1.88Ϫ2.15 (m, 3 H, CH₂CH₃, β-

70.2 (63) [C₅H₁₀^ϩ], 69.2 (24) [C₅H₉^ϩ], 68.2 (13) [C₅H₈^ϩ], 67.2 (15) ring-CH₂), 2.01 (s, 3 H, C₆H₄CH₃), 2.52 (dt, ²J ϭ 9.1 Hz, ³J ϭ

mer, 300 MHz, C₆D₆): δ ϭ 1.07 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃),

[C₅H₇^ϩ], 66.2 (10) [C₅H₆^ϩ], 59.2 (18), 58.2 (27), 57.2 (64) [FeH^ϩ], 8.1 Hz, 1 H, NCH₂), 3.19 (s, 3 H, OCH₃), 3.20 (m, 1 H, OCH₂),

56.1 (78) [Fe^ϩ], 55.2 (78), 54.1 (15), 53.1 (13), 51.1 (13), 45.3 (73)

[H₃COCH₂^ϩ]. Ϫ HR-MS: C₂₂H₃₂⁵⁶FeN₂O: calcd. 396.186340;

found 396.186387.

3.46 (dd, ²J ϭ 9.1 Hz, ³J ϭ 4.0 Hz, 1 H, OCH₂), 3.56 (m, 1 H,

NCH), 4.12 (s, 5 H, C₅H₅), 4.16 (m, 2 H, m-C₅H₄R), 4.99 (dt, ³J ϭ

2.4 Hz, ⁴J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 5.14 (m, 1 H, SCH), 5.16 (dt,

4

3

³J ϭ 2.7 Hz, J ϭ 1.4 Hz, 1 H, o-C₅H₄R), 6.91 (d, J ϭ 8.0 Hz, 2

H, C₆H₄), 7.52 (d, J ϭ 8.0 Hz, 2 H, C₆H₄). Ϫ ¹³C NMR (major

3

SAMP-hydrazone 3l: According to GP3A, a solution of LDA (1.2

equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (6 mL) was treated

with a solution of hydrazone 2c (1.00 g, 2.62 mmol) in diethyl ether

(4 mL). After cooling to Ϫ100 °C, dimethyl disulfide (0.40 mL, 1.7

equiv.) was added dropwise. Aqueous work up and purification by

filtration through silica gel (hexane/diethyl ether ϭ 4:1) provided

hydrazone 3l. Ϫ Yield: 920 mg (82%, red oil). Ϫ R_fϭ 0.48 (hexane/

diethyl ether ϭ 4:1). Ϫ (Z)/(E) Ն 50:1. Ϫ de Ն 96%. Ϫ IR (KBr):

ν˜ ϭ 3083 cm^Ϫ1, 2974, 2961, 2928, 2874, 2848, 2829, 2809, 2731,

2252, 1759, 1671, 1569, 1458, 1438, 1412, 1383, 1352, 1284, 1249,

1192, 1168, 1147, 1121, 1106, 1041, 999, 970, 940, 915, 890, 865,

isomer, 75 MHz, C₆D₆): δ ϭ 12.2, 20.9 (CH₃), 22.4 (NCH₂CH₂),

27.3 (NCHCH₂), 28.4 (CH₂CH₃), 47.9 (SCH), 55.9 (NCH₂), 58.7

(OCH₃), 66.7, 68.8, 69.2, 69.3, 69.5 (C₅H₄R, NCH), 70.5 (C₅H₅),

76.1 (OCH₂), 80.1 (i-C₅H₄R), 130.2, 132.1 (C₆H₄), 133.4, 137.0 (i-

C₆H₄), 166.7 (CϭN). Ϫ ¹³C NMR (minor isomer, 75 MHz, C₆D₆):

δ ϭ 13.4, 21.0 (CH₃), 22.6 (NCH₂CH₂), 27.9, 28.0 (CH₂CH₃,

NCHCH₂), 49.3 (SCH), 56.3 (NCH₂), 58.9 (OCH₃), 67.3, 68.6,

69.2, 69.4, 70.5 (C₅H₄R, NCH), 70.2 (C₅H₅), 76.5 (OCH₂), 80.8 (i-

C₅H₄R), 129.9, 131.9 (C₆H₄), 132.2, 136.5 (i-C₆H₄), 166.8 (CϭN).

Ϫ EI-MS; m/z: 490.1 (52) [M^ϩ], 367.0 (100) [M^ϩϪ H₃CC₆H₄S],

321.0 (16), 254.0 (80) [367.0 Ϫ C₆H₁₁NO], 252.0 (73) [267.0 Ϫ

C₆H₁₃NO], 227.9 (30), 210.9 (35) [FcCN^ϩ], 184.9 (91) [Fc^ϩ], 165.0

(13) [H₃CC₆H₄SCHCHCH₃^ϩ], 156.0 (65), 129.0 (33) [C₁₀H₉^ϩ],

122.9 (29) [C₇H₇S^ϩ], 120.9 (51) [CpFe^ϩ], 91.0 (25) [C₇H₇^ϩ], 71.1

(20), 56.0 (13) [Fe^ϩ], 45.2 (19) [CH₃OCH₂^ϩ]. Ϫ C₂₇H₃₄FeN₂OS

(490.5): calcd. C 66.12, H 6.99, N 5.71; found C 65.90, H 6.70,

N 5.59.

1

842, 807, 729, 691, 629, 524, 484. Ϫ H NMR (300 MHz, C₆D₆):

3

δ ϭ 0.79 (d, ³J ϭ 6.7 Hz, 3 H, CHCH₃), 1.21 (d, J ϭ 6.4 Hz, 3

H, CHCH₃), 1.52Ϫ1.78 (m, 3 H), 1.98Ϫ2.14 (m, 2 H, β-ring-CH₂,

NCH₂), 2.21 (s, 3 H, SCH₃), 2.49 (q, ^2/3J ϭ 8.4 Hz, 1 H, NCH₂),

3.06 [broad m, 1 H, CH(CH₃)₂], 3.18 (s, 3 H, OCH₃), 3.39 (dd,

3

²J ϭ 8.4 Hz, J ϭ 6.4 Hz, 1 H, OCH₂), 3.56 (m, 1 H, NCH), 3.62

(dd, ²J ϭ 8.4 Hz, ³J ϭ 4.4 Hz, 1 H, OCH₂), 4.12 (m, 2 H, m-

C₅H₄R), 4.28 (s, 5 H, C₅H₅), 4.39 (m, 1 H, o-C₅H₄R), 4.98 (broad

3

4

s, 1 H, SCH), 5.06 (dt, J ϭ 2.0 Hz, J ϭ 1.7 Hz, 1 H, o-C₅H₄R).

Ϫ

SAMP-bishydrazone 11: According to GP3A, a solution of LDA

¹³C NMR (75 MHz, C₆D₆): δ ϭ 21.7, 21.8 (CH₃), 22.4 (1.2 equiv.) and LiClO₄(3.0 equiv.) in diethyl ether (6 mL) was

(NCH₂CH₂), 27.3 (NCHCH₂), 31.6 [CH(CH₃)₂], 52.6 (SCH), 56.2 treated with a solution of hydrazone 10 (1.00 g, 2.62 mmol) in di-

(NCH₂), 58.7 (OCH₃), 67.7, 68.5, 68.6, 69.0, 71.7 (NCH, C₅H₄R), ethyl ether (4 mL). After cooling to Ϫ100 °C, dimethyl disulfide

70.2 (C₅H₅), 76.1 (OCH₂), 166.9 (CϭN). Ϫ EI-MS; m/z: 428.2 (87) (0.40 mL, 1.7 equiv.) was added dropwise. Aqueous work up and

[M^ϩ], 381.2 (31) [M^ϩϪ SCH₃], 335.1 (30) [M^ϩϪ HSCH₃

Ϫ

purification by filtration through silica gel (hexane/diethyl ether ϭ

4:1) provided hydrazone 11. Ϫ Yield: 231 mg (50%, orange-red oil).

Ϫ (EE)/(EZ) ϭ 22:1. Ϫ R_fϭ 0.15 (hexane/diethyl ether ϭ 4:1). Ϫ

Me₂O], 314.1 (19) [M^ϩϪ C₆H₁₂NO], 268.1 (36) [314.1 Ϫ H₂Cϭ

S], 267.1 (36) [M^ϩϪ H₂CϭS Ϫ C₆H₁₃NO], 266.1 (100) [314.1 Ϫ

3412

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

4

de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ421.5 (CHCl₃, c ϭ 0.78). Ϫ IR (CHCl₃):

ν˜ ϭ 3099 cm^Ϫ1, 2969, 2919, 2873, 2730, 1674, 1572, 1450, 1377,

C₆H₅), 130.6 (d, J_CPϭ 2.4 Hz), 131.1 (d, J_CPϭ 2.4 Hz, p-C₆H₅),

2

133.8 (d, J_CPϭ 9.8 Hz), 134.0 (d, J_CPϭ 9.1 Hz, o-C₆H₅), 167.1

1340, 1295, 1247, 1198, 1186, 1110, 1049, 1029, 963, 912, 881, 827,

(CϭN). Ϫ ³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ22.0 (minor isomer:

756, 719, 666, 519, 493. Ϫ H NMR (400 MHz, C₆D₆): δ ϭ 1.61 ϩ25.0) (broad). Ϫ EI-MS; m/z: 580.2 (1) [M^ϩ], 566.2 (48) [M^ϩ

Ϫ

1

3

(d, J ϭ 7.7 Hz, 6 H, CHCH₃), 1.63Ϫ2.08 (m, 8 H, β-ring-CH₂),

BH₃], 452.1 (30) [566.1 Ϫ C₆H₁₂NO], 381.1 (100) [566.2 Ϫ PPh₂],

1.90 (s, 6 H, SCH₃), 2.52 (q, ^2/3J ϭ 8.5 Hz, 2 H, NCH₂), 2.93 (ddd,

267.9 (75) [452.1 Ϫ Ph₂PϪBH₂], 266.0 (69) [452.1 Ϫ HPPh₂], 241.0

²J ϭ 11.6 Hz, ³J ϭ 4.6 Hz, ³J ϭ 2.5 Hz, 2 H, NCH₂), 3.12 (s, 6 H, (36), 224.8 (55) [H₃CC₁₀H₈CNFe^ϩ], 184.8 (50) [Fc^ϩ], 183.0 (81),

OCH₃), 3.23 (dd, J ϭ 8.8 Hz, ³J ϭ 7.2 Hz, 2 H, OCH₂), 3.51 (dd,

156.1 (91), 143.0 (23), 121.0 (45) [CpFe^ϩ]. Ϫ C₃₃H₄₂BFeN₂OP

2

²J ϭ 8.8 Hz, ³J ϭ 4.1 Hz, 2 H, OCH₂), 3.58 (qd, ³J ϭ 7.4 Hz, ³J ϭ (580.3): calcd. C 68.30, H 7.29, N 4.83; found C 68.29, H 7.66,

3.9 Hz, 2 H, NCH), 4.22 (m, 2 H, m-C₅H₄R), 4.29 (m, 2 H, m-

N 4.81.

C₅H₄R), 4.90 (q, ³J ϭ 7.4 Hz, 2 H, SCHCH₃), 4.98 (dt, ³J ϭ

4

3

4

Planar Chiral SAMP-hydrazone 4b: According to GP4, a solution

of hydrazone 3d (1.54 g, 2.72 mmol) and LiClO₄(6.0 equiv.) in

THF (30 mL) was first treated with tBuLi (3.0 equiv.) and after-

wards with dimethyl disulfide (0.86 mL, 3.5 equiv.). Aqueous work

up and purification by flash chromatography through silica gel

(hexane/diethyl ether ϭ 4:1) provided hydrazone 4b. Ϫ Yield: 1.08 g

(65%, red crystals). Ϫ R_fϭ 0.20 (hexane/diethyl ether ϭ 4:1). Ϫ de

Ն 90%. Ϫ [α]²_D⁵ϭ Ϫ310.1 (CHCl₃, c ϭ 0.74). Ϫ M.p.: 141 °C. Ϫ

IR (KBr): ν˜ ϭ 3090 cm^Ϫ1, 3051, 2962, 2914, 2885, 2869, 2826,

2806, 2738, 2395, 2348, 2268, 1975, 1910, 1832, 1803, 1740, 1676,

1619, 1569, 1483, 1475, 1437, 1382, 1320, 1275, 1234, 1185, 1139,

1105, 1062, 1000, 965, 946, 914, 886, 812, 767, 736, 693, 643. Ϫ ¹H

NMR (300 MHz, C₆D₆): δ ϭ 1.05 (t, ³J ϭ 7.4 Hz, 3 H, CH₃),

1.65Ϫ2.08 (m, 4 H, CH₂), 1.87 (s, 3 H, SCH₃), 2.22 (m, 1 H, CH₂),

2.56 (broad q, ^2/3J ϭ 8.7 Hz, 1 H, NCH₂), 2.82 (m, 1 H, CH₂),

2.5 Hz, J ϭ 1.4 Hz, 2 H, o-C₅H₄R), 5.23 (dt, J ϭ 2.5 Hz, J ϭ

1.4 Hz, 2 H, o-C₅H₄R). Ϫ ¹³C NMR (100 MHz, C₆D₆): δ ϭ 15.3

(SCH₃), 19.2 (CH₃), 22.5 (NCH₂CH₂), 27.5 (NCHCH₂), 39.3

(SCH), 56.1 (NCH₂), 58.7 (OCH₃), 67.2, 69.2, 71.2, 71.69, 71.71

(C₅H₄R, NCH), 76.3 (OCH₂), 80.0 (i-C₅H₄R), 164.9 (CϭN). Ϫ EI-

MS; m/z: 614.2 (100) [M^ϩ], 568.3 (13) [M^ϩϪ H₂CϭS], 335.1 (56)

[M^ϩϪ C₅H₄R], 187.1 (37), 142.1 (21), 75.1 (19). Ϫ HR-MS:

C₃₀H₄₆⁵⁶FeN₄O₂S₂: calcd. 614.241159; found 614.241145.

General Procedure for the Preparation of Hydrazones 4 (GP4): A

heated Schlenk flask was charged under argon with a solution of

hydrazone 3 in dry THF (10Ϫ20 mL mmol^Ϫ1), then with either 3.0

equiv. (E¹ϭ SR) or 6.0 equiv. (E¹ϭ Ph₂PBH₃) of a 4  LiClO₄

solution in diethyl ether and cooled to Ϫ70 °C. In cases where the

solution became difficult to stir, more THF was added. To this

suspension, either 1.1 equiv. (E¹ϭ SR) or 2.5 to 3.0 equiv. (E¹ϭ

Ph₂PBH₃) tBuLi (1.5 in hexane) was added dropwise and the re-

action mixture was stirred for 7 h at Ϫ70 °C. Afterwards, the elec-

trophile E²X ϭ RSSR or a solution of the electrophile E²X ϭ

Ph₂ClPBH₃in THF was added dropwise. After warming to room

temperature overnight, the reaction mixture was cooled to 0 °C

and quenched with saturated aqueous NH₄Cl (E²ϭ SR) or with

saturated aqueous NaHCO₃(E²ϭ Ph₂PBH₃), washed twice with

brine, and dried with MgSO₄. The crude product was filtered

through silica gel (hexane/ether ϭ 4:1) and dried under high va-

cuum.

2

3.13 (m, 1 H, NCH₂), 3.21 (s, 3 H, OCH₃), 3.42 (dd, J ϭ 9.1 Hz,

³J ϭ 4.7 Hz, 1 H, OCH₂), 3.48 (dd, ²J ϭ 9.1 Hz, ³J ϭ 6.0 Hz, 1

3

H, OCH₂), 3.64 (m, 1 H, NCH), 3.94 (s, 5 H, C₅H₅), 3.95 (t, J ϭ

2.7 Hz, C₅H₃R₂), 4.03 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ 1.3 Hz, 1 H,

3

4

C₅H₃R₂), 5.15 (dd, J ϭ 2.7 Hz, J ϭ 1.3 Hz, 1 H, C₅H₃R₂), 5.20

(m, 1 H, PCH), 6.88 (m, 3 H), 7.06Ϫ7.20 (m, 3 H, m/p-C₆H₅), 7.70

(ddd, J ϭ 9.4 Hz, J ϭ 8.1 Hz, J ϭ 1.7 Hz, 2 H, o-C₆H₅), 8.50 (ddd,

J ϭ 9.7 Hz, J ϭ 8.7 Hz, J ϭ 1.7 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR

(75 MHz, C₆D₆): δ ϭ 16.1, 17.7 (CH₃), 23.5 (NCH₂CH₂), 25.0

1

(CH₂CH₃), 27.4 (NCHCH₂), 41.0 (d, J_CPϭ 26.9 Hz, PCH), 57.7

(NCH₂), 59.5 (OCH₃), 67.1, 68.0, 70.3, 70.6 (NCH, C₅H₃R₂), 72.3

(C₅H₅), 75.5 (OCH₂), 79.5, 92.1 (i-C₅H₃R₂), 128.3 (d, J_CP

ϭ

1

Planar Chiral SAMP-hydrazone 4a: According to GP4, a solution

of hydrazone 3d (141 mg, 0.249 mmol) and LiClO₄(6.0 equiv.) in

THF (4 mL) was first treated with tBuLi (4.0 equiv.) and after-

wards with methyl iodide (69 µL, 4.5 equiv.). Aqueous work up

and purification by flash chromatography through silica gel (hex-

ane/diethyl ether ϭ 7:1) provided hydrazone 4a. Ϫ Yield: 80 mg

(55%, orange crystals). Ϫ R_fϭ 0.33 (hexane/diethyl ether ϭ 4:1).

Ϫ de ϭ 96%. Ϫ [α]²_D⁵ϭ Ϫ86.9 (CHCl₃, c ϭ 0.82). Ϫ M.p.: 147 °C.

Ϫ IR (KBr): ν˜ ϭ 3090 cm^Ϫ1, 3051, 2924, 2855, 2802, 2738, 2395,

2344, 2268, 1909, 1806, 1737, 1721, 1685, 1657, 1626, 1568, 1525,

1456, 1437, 1383, 1342, 1320, 1284, 1244, 1205, 1173, 1142, 1105,

8.5 Hz), 129.4 (d, J_CPϭ 9.7 Hz, m-C₆H₅), 129.8 (d, J_CP

ϭ

1

62.0 Hz), 133.2 (d, J_CPϭ 53.2 Hz, i-C₆H₅), 130.8, 131.7 (p-C₆H₅),

134.2 (d, J_CPϭ 9.2 Hz), 134.4 (d, J_CPϭ 8.6 Hz, o-C₆H₅), 165.4

(CϭN). Ϫ ³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ22.1 (broad). Ϫ EI-

MS; m/z: 598.1 (11) [M^ϩϪ BH₃], 484.0 (24) [598.1 Ϫ C₆H₁₂NO],

430.1 (13), 413.0 (38) [598.1 Ϫ PPh₂], 300.0 (17), 297.9 (13), 284.9

(46), 282.9 (36), 256.9 (12), 254.0 (10), 241.8 (12), 217.0 (11), 207.0

(11), 186.0 (12) [Cp₂Fe^ϩ], 185.0 (34) [PPh₂^ϩ], 184.0 (10), 183.0 (37)

[Ph₂P^ϩϪ H₂], 156.1 (100). Ϫ C₃₃H₄₂BFeN₂OPS (612.4): calcd. C

64.72, H 6.91, N 4.57; found C 64.66, H 7.17, N 4.53.

1062, 999, 988, 889, 816, 802, 738, 693, 660, 619. Ϫ ¹H NMR Planar Chiral SAMP-hydrazone 4c: According to GP4, a solution

(300 MHz, C₆D₆): δ ϭ 1.00 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), of hydrazone 3c (1.69 g, 3.06 mmol) and LiClO₄(6.0 equiv.) in

1.60Ϫ2.14 (m, 6 H, CH₂CH₃, β-ring-CH₂), 1.88 (s, 3 H, H₃CCp), THF (20 mL) was first treated with tBuLi (2.5 equiv.) and after-

2

3

2

2.47 (dt, J ϭ 9.4 Hz, J ϭ 8.1 Hz, 1 H, NCH₂), 3.10 (ddd, J ϭ

wards with dimethyl disulfide (0.77 mL, 2.8 equiv.). Aqueous work

9.7 Hz, ³J ϭ 7.1 Hz, ³J ϭ 4.4 Hz, 1 H, NCH₂), 3.19 (s, 3 H, OCH₃), up and purification by filtration through silica gel (hexane/diethyl

3.30Ϫ3.40 (m, 3 H, OCH₂, NCH), 3.92 (s, 5 H, C₅H₅), 3.93 (m, 1 ether ϭ 7:1) provided hydrazone 4c. Ϫ Yield: 1.72 g (94%, red

H, C₅H₃R₂), 3.95 (m, 1 H, C₅H₃R₂), 4.87 (m, 1 H, C₅H₃R₂), 5.27 crystals). Ϫ R_fϭ 0.33 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 90%.

2

(ddd, J_HPϭ 14.4 Hz, ³J ϭ 9.7 Hz, ³J ϭ 4.0 Hz, PCH), 6.89 (m, 3

Ϫ [α]²_D⁵ϭ Ϫ287.9 (CHCl₃, c ϭ 1.25). Ϫ Mp: 146 °C. Ϫ IR (CHCl₃):

H), 7.06 (m, 1 H), 7.12 (m, 2 H, m/p-C₆H₅), 7.67 (m, 2 H, o-C₆H₅), ν˜ ϭ 3081 cm^Ϫ1, 3056, 2973, 2920, 2873, 2829, 2736, 2387, 2278,

8.39 (ddm, ³J_HPϭ 9.4 Hz, ³J ϭ 7.7 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR

1574, 1438, 1385, 1354, 1335, 1315, 1278, 1242, 1218, 1187, 1106,

(75 MHz, C₆D₆): δ ϭ 15.4, 15.8 (CH₃), 22.9 (NCH₂CH₂), 24.7, 1058, 1030, 1001, 970, 905, 878, 818, 756, 699, 666, 649, 560, 517,

1

27.0 (CH₂CH₃, NCHCH₂), 40.2 (d, J_CPϭ 28.7 Hz, PCH), 57.1 501, 470, 454. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ 1.55Ϫ2.12 (m,

(NCH₂), 59.1 (OCH₃), 66.6, 67.9, 70.0, 71.9 (NCH, C₅H₃R₂), 71.0 4 H, β-ring-CH₂), 1.82 (dd, J_HPϭ 16.8 Hz, ³J ϭ 7.7 Hz, 3 H,

3

(C₅H₅), 75.4 (OCH₂), 86.9 (i-C₅H₃R₂), 128.9 (d, ³J_CPϭ 9.7 Hz, m-

CHCH₃), 1.86 (s, 3 H, SCH₃), 2.47 (td, ^2/3J ϭ 9.1 Hz, ³J ϭ 7.4 Hz,

1

2

3

C₆H₅), 129.8 (d, J_CPϭ 53.5 Hz), 132.6 (d, J_CPϭ 51.9 Hz, i-

1 H, NCH₂), 3.08 (ddd, J ϭ 9.7 Hz, J ϭ 7.7 Hz, J ϭ 5.4 Hz, 1

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3413

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

H, NCH₂), 3.22 (s, 3 H, OCH₃), 3.41 (dd, ²J ϭ 9.1 Hz, ³J ϭ 7.1 Hz, ane/diethyl ether ϭ 4:1) provided hydrazone 4e. Ϫ Yield: 104 mg

1 H, OCH₂), 3.54 (dd, ²J ϭ 9.1 Hz, ³J ϭ 4.0 Hz, 1 H, OCH₂), 3.72 (83%, yellow oil). Ϫ R_fϭ 0.50 (hexane/diethyl ether ϭ 4:1). Ϫ de

3

(qd, J ϭ 7.7 Hz, J ϭ 3.7 Hz, 1 H, NCH), 3.92 (t, J ϭ 2.7 Hz, 1 Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ90.2 (CHCl₃, c ϭ 0.66). Ϫ IR (KBr): ν˜ ϭ 3086

H, C₅H₃R₂), 3.93 (s, 5 H, C₅H₅), 4.02 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ cm^Ϫ1, 2962, 2923, 2872, 2825, 2724, 2247, 2066, 1704, 1659, 1561,

1.3 Hz, 1 H, C₅H₃R₂), 5.11 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ 1.4 Hz, 1 H, 1454, 1426, 1377, 1345, 1277, 1254, 1231, 1159, 1129, 1104, 1047,

C₅H₃R₂), 5.14 (dq, J_HPϭ 16.5 Hz, ³J ϭ 7.7 Hz, 1 H, PCH),

1001, 970, 905, 882, 822, 797, 718, 679, 650, 592, 490. Ϫ H NMR

2

1

6.88Ϫ7.13 (m, 6 H, 1 H, m/p-C₆H₅), 7.78 (ddd, J ϭ 9.7 Hz, J ϭ (300 MHz, C₆D₆): δ ϭ 1.17 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃),

8.4 Hz, J ϭ 1.7 Hz, 2 H), 8.29 (ddd, J ϭ 9.7 Hz, J ϭ 8.5 Hz, J ϭ

1.4 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 15.6

1.55Ϫ2.05 (m, 6 H, CH₂CH₃, β-ring-CH₂), 1.84 (s, 3 H, SCH₃),

2.42 (s, 3 H, CpCH₃), 2.46 (m, 1 H, NCH₂), 3.02 (ddd, ²J ϭ 9.1 Hz,

2

3

(d, J_CPϭ 4.3 Hz, CHCH₃), 17.3 (SCH₃), 22.9 (NCH₂CH₂), 27.0

³J ϭ 7.7 Hz, J ϭ 4.4 Hz, 1 H, NCH₂), 3.13 (s, 3 H, OCH₃), 3.27

1

(NCHCH₂), 33.2 (d, J_CPϭ 28.6 Hz, CHCH₃), 56.8 (NCH₂), 59.0

(m, 1 H, OCH₂), 3.48 (m, 2 H, OCH₂, NCH), 3.99 (t, ³J ϭ 2.7 Hz,

(OCH₃), 66.7, 67.4, 67.5, 69.9 (NCH, C₅H₃R₂), 71.7 (C₅H₅), 75.5 1 H, C₅H₄R), 4.03 (s, 5 H, C₅H₅), 4.13 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ

(OCH₂), 79.0, 91.0 (i-C₅H₃R₂), 128.9 (d, J_CPϭ 9.8 Hz, m-C₆H₅), 1.3 Hz, 1 H, C₅H₄R), 4.50 (dd, ³J ϭ 2.8 Hz, ⁴J ϭ 1.4 Hz, 1 H,

3

133.61 (d, J_CPϭ 9.1 Hz), 133.63 (d, J_CPϭ 8.6 Hz, o-C₆H₅), 129.8

C₅H₄R), 4.65 (dd, J ϭ 10.2 Hz, J ϭ 5.0 Hz, 1 H, SCH). Ϫ ¹³C

1

(d, J_CPϭ 48.2 Hz), 132.0 (d, J_CPϭ 51.7 Hz, i-C₆H₅), 130.7 (d, NMR (75 MHz, C₆D₆): δ ϭ 14.2, 15.7, 17.4 (SCH₃, CH₃), 23.0

⁴J_CPϭ 2.4 Hz), 131.1 (d, ⁴J_CPϭ 2.5 Hz, p-C₆H₅), 163.7 (CϭN). Ϫ (NCH₂CH₂), 27.4, 27.8 (CH₂CH₃, NCHCH₂), 48.6 (SCH), 57.4

³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ24.1 (broad). Ϫ EI-MS; m/z:

(NCH₂), 59.3 (OCH₃), 67.1, 67.9, 70.2, 72.1 (C₅H₄R, NCH), 71.3

584.2 (5) [M^ϩϪ BH₃], 399.0 (14) [384.2 Ϫ Ph₂P], 271.0 (21), 268.9 (C₅H₅), 76.5 (OCH₂), 80.6, 86.6 (i-C₅H₄R), 168.3 (CϭN). Ϫ EI-

(11) [399.0 Ϫ C₆H₁₄N₂O], 185.1 (14) [Ph₂P^ϩ], 183.0 (21) [Ph₂P^ϩMS; m/z: 428.1 (100) [M^ϩ], 381.0 (11) [M^ϩϪ CH₃S], 335.1 (15)

H₂], 142.1 (100), 121.0 (13) [CpFe^ϩ]. Ϫ C₃₂H₄₀BFeN₂OPS (598.4): [M^ϩϪ CH₃SH Ϫ CH₂OCH₃], 314.1 (10) [M^ϩϪ C₆H₁₂NO], 268.1

Ϫ

calcd. C 64.23, H 6.74, N 4.68; found C 64.01, H 6.62, N 4.57.

(16), 267.3 (12), 266.0 (37) [314.1 Ϫ CH₃SH], 243.9 (11), 241.0 (17),

226.0 (23), 224.9 (73) [C₈H₁₀FeCH₃CN^ϩ], 158.8 (15), 156.1 (40),

143.0 (15), 133.8 (12), 121.0 (54) [CpFe^ϩ], 90.9 (12), 89.1 (61), 45.3

Planar Chiral SAMP-hydrazone 4d: According to GP4, a solution

of hydrazone 3i (140 mg, 0.289 mmol) and LiClO₄(6.0 equiv.) in

THF (6 mL) was first treated with tBuLi (2.5 equiv.) and after-

wards with a solution of di-p-tolyl disulfide (249 mg, 3.5 equiv.) in

THF (1 mL). Aqueous work up and purification by filtration

through silica gel (hexane/diethyl ether ϭ 7:1) provided hydrazone

4d. Ϫ Yield: 133 mg (76%, orange powder). Ϫ R_fϭ 0.61 (hexane/

diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ294.2 (CHCl₃, c ϭ

(18) [CH₃OCH₂^ϩ].

Ϫ

HR-MS: C₂₂H₃₂⁵⁶FeN₂OS: calcd.

428.158472; found 428.158957.

Planar Chiral SAMP-hydrazone 4f: According to GP4, a solution

of hydrazone 3e (2.00 g, 5.00 mmol) and LiClO₄(3.0 equiv.) in

THF (30 mL) was first treated with tBuLi (1.2 equiv.) and after-

wards with a solution of Ph₂PCl·BH₃(1.3 equiv.) in THF (3 mL).

0.59). Ϫ M.p.: 133 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3096 cm^Ϫ1, 1964, 2932, Aqueous work up and purification by filtration through silica gel

2874, 2828, 2379, 1597, 1568, 1492, 1461, 1412, 1387, 1354, 1320,

(hexane/diethyl ether ϭ 4:1) provided hydrazone 4f. Ϫ Yield: 2.57 g

1302, 1218, 1183, 1107, 1057, 1002, 970, 906, 886, 813, 757, 684, (86%, orange crystals). Ϫ R_fϭ 0.23 (hexane/diethyl ether ϭ 4:1).

1

667, 631, 507, 488. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ 0.94 (dd, Ϫ de ϭ 96%. Ϫ [α]²_D⁵ϭ ϩ10.8 (CHCl₃, c ϭ 0.69). Ϫ M.p.: 131 °C.

³J_HPϭ 12.6 Hz, ³J ϭ 6.9 Hz, 3 H), 1.07 (dd, ³J_HPϭ 15.1 Hz, ³J ϭ

Ϫ IR (CHCl₃): ν˜ ϭ 3078 cm^Ϫ1, 3056, 3001, 2970, 2920, 2873, 2826,

2734, 2615, 2586, 2392, 2279, 2112, 1960, 1892, 1814, 1775, 1664,

1588, 1573, 1484, 1450, 1436, 1383, 1355, 1342, 1324, 1282, 1218,

3

7.2 Hz, 3 H), 1.11 (dd, J_HPϭ 12.9 Hz, ³J ϭ 7.1 Hz, 3 H), 1.16

3

(dd, J_HPϭ 13.7 Hz, J ϭ 7.1 Hz, 3 H, P[CH(CH₃)₂]₂), 1.60Ϫ2.03

[m, 6 H, β-ring-CH_2,PCH(CH₃)₂], 2.06 (s, 3 H, C₆H₄CH₃), 1.76 1197, 1162, 1137, 1107, 1060, 1029, 1002, 971, 910, 825, 753, 696,

2

3

2/

(dd, J_HPϭ 14.5 Hz, J ϭ 7.7 Hz, 3 H, NϭCCHCH₃), 2.49 (td,

667, 633, 608, 550, 524. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ

³J ϭ 9.1 Hz, J ϭ 8.0 Hz, 1 H, NCH₂), 3.13 (s, 3 H, OCH₃), 3.15 1.55Ϫ2.15 (m, 4 H, β-ring-CH₂), 1.66 (d, ³J ϭ 7.7 Hz, 3 H,

3

2

3

2

3

(m, 1 H, NCH₂), 3.35 (dd, J ϭ 9.3 Hz, J ϭ 6.3 Hz, 1 H, OCH₂),

3.52 (dd, ²J ϭ 9.3 Hz, ³J ϭ 3.7 Hz, 1 H, OCH₂), 3.64 (m, 1 H,

CHCH₃), 1.79 (s, 3 H, SCH₃), 2.18 (dd, J ϭ 9.1 Hz, J ϭ 3.7 Hz,

1 H, OCH₂), 2.30 (dd, ²J ϭ 9.1 Hz, ³J ϭ 3.7 Hz, 1 H, OCH₂), 2.89

NCH), 3.99 (t, ³J ϭ 2.7 Hz, 1 H, C₅H₃R₂), 4.03 (s, 5 H, C₅H₅), (s, 3 H, OCH₃), 3.00Ϫ3.20 (m, 2 H, NCH₂), 3.41 (td, J ϭ J_HP

ϭ

3

4.13 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.23 (dq, ²J_HPϭ

2.7 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.01 (td, J ϭ 2.7 Hz, J_HP

0.7 Hz, 1 H, C₅H₃R₂), 4.32 (s, 5 H, C₅H₅), 4.79 (q, J ϭ 7.7 Hz, 1

ϭ

4

3

4

3

4

3

16.2 Hz, J ϭ 7.7 Hz, 1 H, NϭCCH), 5.20 (dd, J ϭ 3.0 Hz, J ϭ

1.4 Hz, 1 H, C₅H₃R₂), 6.90 (br. d, J ϭ 7.7 Hz, 2 H, C₆H₄), 7.41 H, CHCH₃), 5.26 (dt, ³J ϭ 3.0 Hz, ⁴J ϭ J_HPϭ 1.4 Hz, 1 H,

3

4

3

4

3

(dt, J ϭ 8.0 Hz, J ϭ 1.7 Hz, 2 H, C₆H₄). Ϫ ¹³C NMR (75 MHz, C₅H₃R₂), 6.96Ϫ7.05 (m, 6 H, m/p-C₆H₅), 7.64 (tm, J ϭ 8.0 Hz, 2

1

C₆D₆): δ ϭ 16.7, 17.6, 17.9, 18.5, 18.8, 21.0 (CH₃), 22.3 (d, J_CP

31.8 Hz), 24.7 (d, J_CPϭ 30.3, PCH), 22.7 (NCH₂CH₂), 26.4 (75 MHz, C₆D₆): δ ϭ 15.0, 18.8 (CH₃, SCH₃), 24.4 (NCH₂CH₂),

(NCHCH₂), 27.9 (d, J_CPϭ 22.9, PCH) 56.6 (NCH₂), 58.7

ϭ

H, o-C₆H₅), 7.77 (tm, ³J ϭ 7.5 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR

1

28.0 (NCHCH₂), 39.7 (SCH), 58.4 (OCH₃), 59.2 (NCH₂), 64.8

(OCH₃), 67.5, 68.0, 71.1, 72.5 (C₅H₃R₂, NCH), 72.1 (C₅H₅), 74.6 (NCH), 70.9 (d, J_CPϭ 5.5 Hz), 74.1 (d, J_CPϭ 5.5 Hz), 76.0 (d,

(OCH₂), 80.1, 87.3 (i-C₅H₃R₂), 129.9, 131.7 (C₆H₄), 135.4, 136.4

(i-C₆H₄), 163.0 (CϭN). Ϫ ³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ43.0

(broad). Ϫ CI-MS (isobutane); m/z: 606.3 (56) [M^ϩ], 605.2 (100)

J

_CPϭ 4.3 Hz, C₅H₃R₂), 71.6 (C₅H₅), 74.9 (OCH₂), 85.2 (d, ¹J_CPϭ

2

9.0 Hz, C₅H₃R₂), 129.7, 130.2 (p-C₆H₅), 132.5 (d, J_CPϭ 8.0 Hz),

2

1

134.5 (d, J_CPϭ 7.9 Hz, o-C₆H₅), 135.4 (d, J_CPϭ 53.7 Hz, i-

[M^ϩϪ H], 593.2 (31) [MH^ϩϪ BH₃], 592.2 (15) [M^ϩϪ BH₃], 549.1 C₆H₅). Ϫ ³¹P NMR (C₆D₆, 162 MHz): ϩ19.0 (broad). Ϫ EI-MS;

(13) [592.2 Ϫ CH(CH₃)₂], 492.1 (18) [M^ϩϪ C₆H₁₂NO], 116.1 (11)

m/z: 537.1 (27) [M^ϩϪ BH₃Ϫ SCH₃], 424.0 (51) [M^ϩϪ BH₃

Ϫ

[(H₃C)₂CϭPCH(CH₃)₂^ϩ]. Ϫ C₃₂H₄₈BFeN₂OPS (606.4): calcd. C H₂CϭS Ϫ C₆H₁₂NO], 240.0 (36), 186.0 (33) [Cp₂Fe^ϩ], 185.0 (100)

62.01, H 8.74, N 5.78; found C 62.18, H 8.67, N 6.27.

[PPh₂^ϩ]. Ϫ C₃₂H₄₀BFeN₂OPS (598.4): calcd. C 64.23, H 6.74, N

4.68; found C 64.24, H 6.60, N 4.66.

Planar Chiral SAMP-hydrazone 4e: According to GP4, a solution

of hydrazone 3f (123 mg, 0.249 mmol) and LiClO₄(3.0 equiv.) in

THF (3.5 mL) was first treated with tBuLi (1.3 equiv.) and after-

wards with methyl iodide (31 µL, 1.7 equiv.). Aqueous work up

and purification by flash chromatography through silica gel (hex-

Planar Chiral SAMP-hydrazone 4g: According to GP4, a solution

of hydrazone 3f (2.31 g, 5.57 mmol) and LiClO₄(3.0 equiv.) in THF

(30 mL) was first treated with tBuLi (1.1 equiv.) and afterwards

with a solution of Ph₂PCl·BH₃(1.3 equiv.) in THF (3 mL). Aque-

3414

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

ous work up and purification by flash chromatography through PCH), 27.7, 28.1 (CH₂CH₃, NCHCH₂), 48.7 (SCH), 57.8 (NCH₂),

FULL PAPER

silica gel (hexane/diethyl ether ϭ 4:1) provided hydrazone 4g. Ϫ

Yield: 2.62 g (77%, orange powder). Ϫ R_fϭ 0.47 (hexane/diethyl

ether ϭ 4:1). Ϫ de Ն 90%. Ϫ [α]²_D⁵ϭ Ϫ35.2 (CHCl₃, c ϭ 0.52). Ϫ

58.8 (OCH₃), 66.1 (NCH), 71.1 (d, J_CPϭ 8.5 Hz), 75.5 (d, J_CPϭ

4.2 Hz), 78.4 (d, J_CPϭ 13.4 Hz, C₅H₃R₂), 71.8 (C₅H₅), 76.3

(OCH₂), 165.3 (CϭN). Ϫ ³¹P NMR (121 MHz, C₆D₆): δ ϭ ϩ36.6

M.p.: 133 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3076 cm^Ϫ1, 3056, 2969, 2921, (broad). Ϫ CI-MS (isobutane); m/z: 544.2 (40) [M^ϩ], 543.1 (100)

2872, 2826, 2391, 2351, 2279, 1588, 1437, 1385, 1325, 1278, 1218,

[M^ϩϪ H], 31.1 (2) [MH^ϩϪ BH₃], 497.2 (15) [M^ϩϪ SCH₃], 496.3

1187, 1160, 1136, 1107, 1060, 1029, 1003, 970, 948, 906, 825, 755, (16) [M^ϩϪ HSCH₃], 495.2 (2), 483.0 (28) [497.2 Ϫ BH₃], 430.0

696, 667, 631, 524, 499. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ1.25 (t, (20) [M^ϩϪ C₆H₁₂NO], 415.9 (15) [430.0 Ϫ BH₃], 75.2 (17). Ϫ

³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.57Ϫ2.12 (m, 7 H, CH₂CH₃, β-ring-

CH₂, NCH₂), 1.80 (s, 3 H, SCH₃), 2.17 (dd, ²J ϭ 8.7 Hz, ³J ϭ

C₂₇H₄₆BFeN₂OPS (544.4): calcd. C 59.57, H 8.52, N 5.15; found

C 59.94, H 8.63, N 4.74.

2

3

6.3 Hz, OCH₂), 2.88 (s, 3 H, OCH₃), 3.13 (dd, J ϭ 8.5 Hz, J ϭ

3

Planar Chiral SAMP-hydrazone 4i: According to GP4, a solution

of hydrazone 3g (1.05 g, 2.45 mmol) and LiClO₄(3.0 equiv.) in

THF (25 mL) was first treated with tBuLi (1.2 equiv.) and after-

wards with a solution of Ph₂PClBH₃(1.6 equiv.) in THF (6 mL).

Aqueous work up and purification by filtration through silica gel

(hexane/diethyl ether ϭ 4:1) provided hydrazone 4i. Ϫ Yield: 1.11 g

(73%, orange powder). Ϫ R_fϭ 0.25 (hexane/diethyl ether ϭ 4:1).

Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ25.7 (CHCl₃, c ϭ 0.51). Ϫ M.p.: 143 °C.

Ϫ IR (CHCl₃): ν˜ ϭ 3077 cm^Ϫ1, 3056, 3000, 2967, 2926, 2868, 2825,

2432, 2391, 2353, 2259, 1588, 1573, 1550, 1483, 1451, 1436, 1413,

1383, 1366, 1341, 1326, 1283, 1247, 1218, 1198, 1161, 1137, 1107,

6.1 Hz, 1 H, OCH₂), 3.25 (m, 1 H, NCH₂), 3.44 (td, J ϭ 2.5 Hz,

⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 3.84 (m, 1 H, NCH), 4.06 (td, ³J ϭ

4

2.8 Hz, J_HPϭ 0.6 Hz, 1 H, C₅H₃R₂), 4.34 (s, 5 H, C₅H₅), 4.56

3

(dd, J ϭ 10.4 Hz, J ϭ 4.1 Hz, 1 H, SCH), 5.17 (dt, J ϭ 2.4 Hz,

⁴J ϭ J_HPϭ 1.4 Hz, 1 H, C₅H₃R₂), 6.92Ϫ7.07 (m, 5 H), 7.43 (ddd,

J ϭ 9.6 Hz, J ϭ 8.0 Hz, J ϭ 1.7 Hz, 1 H, m/p-C₆H₅), 7.64 (tm,

³J ϭ 8.5 Hz, 2 H), 7.76 (tm, J ϭ 8.0, 2 H, o-C₆H₅). Ϫ ¹³C NMR

3

(75 MHz, C₆D₆): δ ϭ 14.2, 14.7 (CH₃), 24.3 (NCH₂CH₂), 26.3,

27.8 (CH₂CH₃, NCHCH₂), 47.9 (SCH), 58.3 (OCH₃), 59.3

1

(NCH₂), 64.8 (NCH), 68.2 (d, J_CPϭ 65.9, i-C₅H₃R₂), 70.7 (d,

J

_CPϭ 6.9 Hz), 74.3 (d, J_CPϭ 5.2 Hz), 74.7 (C₅H₃R₂), 71.5 (C₅H₅),

1

2

1060, 1003, 973, 911, 825, 756, 696, 667, 638, 617, 593, 562. Ϫ H

75.9 (OCH₂), 85.7 (d, J_CPϭ 7.5 Hz, i-C₅H₃R₂), 129.1 (d, J_CP

ϭ

NMR (300 MHz, C₆D₆): δ ϭ 1.14 (d, ³J ϭ 7.1 Hz, 3 H, SCHCH₃),

10.3 Hz), 132.4 (d, J_CPϭ 8.6 Hz, m-C₆H₅), 133.2 (d, J_CPϭ 9.2 Hz),

3

4

1.25 (d, J ϭ 6.4 Hz, 3 H, SCHCH₃), 1.53Ϫ2.23 (m, 4 H, β-ring-

134.5 (d, J_CPϭ 8.0 Hz, o-C₆H₅), 129.6 (d, J_CPϭ 2.3 Hz), 130.1

CH₂), 1.71 (d, ³J ϭ 7.7 Hz, 3 H, NϭCCHCH₃), 2.30 (dd, ²J ϭ

6.1 Hz, ³J ϭ 1.7 Hz, 2 H, OCH₂), 2.67 [sept, ³J ϭ 7.1 Hz, 1 H,

SCH(CH₃)₂], 2.94 (s, 3 H, OCH₃), 3.06 (td, ^2/3J ϭ 8.7 Hz, ³J ϭ

6.0 Hz, 1 H, NCH₂), 3.26 (dt, ²J ϭ 8.7 Hz, ³J ϭ 7.1 Hz, 1 H,

4

1

(d, J_CP1.7 Hz, p-C₆H₅), 135.3 (d, J_CPϭ 49.9 Hz), 135.6 (d,

¹J_CPϭ 60.7 Hz, i-C₆H₅), 156.2 (d, J_CPϭ 2.2 Hz, CϭN). Ϫ ³¹P

3

NMR (121 MHz, C₆D₆): δ ϭ ϩ18.8 (broad). Ϫ EI-MS; m/z: 484.0

(9) [M^ϩϪ BH₃Ϫ C₆H₁₂NO], 438.0 (15) [484.0 Ϫ H₂CϭS], 199.1

3

4

ϩ

(11) [Ph₂PϪBH₃^ϩ], 185.0 (19) [PPh₂^ϩ], 183.0 (16) [PPh₂Ϫ H₂],

NCH₂), 3.39 (td, J ϭ J_HPϭ 2.7 Hz, J ϭ 1.3 Hz, 1 H, C₅H₃R₂),

3

121.0 (11) [CpFe^ϩ], 83.2 (13), 70.2 (13), 66.2 (100) [C₅H₆^ϩ], 65.1

(75) [Cp^ϩ], 63.2 (11), 48.2 (57), 47.1 (82) [H₃CS^ϩ], 45.3 (37)

[H₃COCH₂^ϩ]. Ϫ C₃₃H₄₂BFeN₂OPS (612.4): calcd. C 64.72, H 6.91,

N 4.57; found C 65.09, H 7.09, N 4.24.

3.96 (m, 1 H, NCH), 4.00 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.33 (s,

3

5 H, C₅H₅), 4.79 (q, J ϭ 7.4 Hz, 1 H, NϭCCH), 5.29 (dt, J ϭ

2.7 Hz, ⁴J ϭ J_HPϭ 1.3 Hz, 1 H, C₅H₃R₂), 7.03 (m, 6 H, m/p-

4

C₆H₅), 7.65 (m, 2 H, o-C₆H₅), 7.77 (m, 2 H, o-C₆H₅). Ϫ ¹³C NMR

(75 MHz, C₆D₆): δ ϭ 19.9, 23.9, 25.0 (CH₃), 24.4 (NCH₂CH₂),

28.0 (NCHCH₂), 36.0, 37.6 (SCH), 58.4 (OCH₃), 59.5 (NCH₂),

64.9 (NCH), 70.7 (d, J_CPϭ 6.7 Hz), 74.0 (d, J_CPϭ 4.9 Hz), 76.0

(d, J_CPϭ 4.3 Hz, C₅H₃R₂), 71.5 (C₅H₅), 75.3 (OCH₂), 129.5, 130.1

Planar Chiral SAMP-hydrazone 4h: According to GP4, a solution

of hydrazone 3f (210 mg, 0.507 mmol) and LiClO₄(3.0 equiv.) in

THF (6 mL) was first treated with tBuLi (1.2 equiv.) and after-

wards with iPr₂PCl (1.3 equiv.) in THF (3 mL). After warming to

room temperature overnight, the solution was cooled down to 0

°C, treated with 1.7 equiv. BH₃DMS and stirred for 3 h. Aqueous

work up and purification by filtration through silica gel (hexane/

diethyl ether ϭ 4:1) provided hydrazone 4h. Ϫ Yield: 257 mg (93%,

orange-red crystals). Ϫ R_fϭ 0.37 (hexane/diethyl ether ϭ 4:1). Ϫ

de Ն 90%. Ϫ [α]²_D⁵ϭ ϩ52.6 (CHCl₃, c ϭ 0.67). Ϫ M.p.: 90 °C. Ϫ

IR (CHCl₃): ν˜ ϭ 3098 cm^Ϫ1, 2965, 2927, 2872, 2731, 2377, 2278,

1711, 1660, 1565, 1461, 1384, 1322, 1284, 1252, 1219, 1200, 1109,

1060, 1005, 967, 946, 931, 886, 824, 757, 688, 667, 647, 578, 496,

2

(p-C₆H₅), 132.5 (d, J_CPϭ 8.6 Hz), 134.5 (d, J_CPϭ 7.9 Hz, o-

1

C₆H₅), 135.2 (d, J_CPϭ 61.0 Hz), 135.3 (d, J_CPϭ 49.4 Hz, i-

C₆H₅), 157.0 (CϭN). Ϫ ³¹P NMR (C₆D₆, 162 MHz): ϩ19.2

(broad). Ϫ CI-MS (isobutane): m/z: 627.2 (5) [MH^ϩ], 626.2 (3)

[M^ϩ], 625.2 (5) [M^ϩϪ H], 613.0 (50) [627.2 Ϫ BH₃], 537.2 (100)

[610.0 Ϫ HSCH(CH₃)₂], 498.0 (26) [M^ϩϪ BH₃Ϫ C₆H₁₂NO],

424.0 (18) [498.0 Ϫ SϭC(CH₃)₂], 128.0 (15) [C₁₀H₈^ϩ], 126.0 (11),

116.1 (20), 114.0 (11) [C₆H₁₂NO^ϩ], 77.2 (11) [H₂SCH(CH₃)₂^ϩ]. Ϫ

C₃₄H₄₄BFeN₂OPS (626.4): calcd. C 65.19, H 7.08, N 4.47; found

C 65.24, H 7.05, N 4.19.

462. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 1.07 (dd, ³J_HPϭ 13.1 Hz,

3

³J ϭ 7.1 Hz, 3 H, PCHCH₃), 1.18 (t, J ϭ 7.4 Hz, 3 H, CH₂CH₃), Planar Chiral SAMP-hydrazone 4j: According to GP4, a solution

3

1.26 (dd, J_HPϭ 14.8 Hz, J ϭ 7.1 Hz, 6 H, PCHCH₃), 1.55 (dd,

of hydrazone 3f (1.55 g, 3.75 mmol) and LiClO₄(4.0 equiv.) in THF

³J_HPϭ 15.5 Hz, ³J ϭ 7.4 Hz, 3 H, PCHCH₃), 1.60Ϫ1.68 (m, 3 H), (30 mL) was first treated with tBuLi (2.0 equiv.) and afterwards

1.93Ϫ2.12 (m, 3 H, CH₂CH₃, β-ring-CH₂), 1.86 (s, 3 H, SCH₃), with dimethyl disulfide (0.81 mL, 2.4 equiv.). Aqueous work up and

2

2.34 (dsept, J_HPϭ 10.7 Hz, ³J ϭ 7.1 Hz, 1 H, PCH), 2.59 (dt,

purification by flash chromatography through silica gel (hexane/

diethyl ether ϭ 4:1) provided hydrazone 4j. Ϫ Yield: 1.70 g (98%,

3

²J ϭ 9.1 Hz, J ϭ 8.1 Hz, 1 H, NCH₂), 3.04 (s, 3 H, OCH₃), 3.10

2

3

(dd, J ϭ 9.1 Hz, J ϭ 6.7 Hz, 1 H, OCH₂), 3.10 (m, 1 H, NCH), orange powder). Ϫ R_fϭ 0.50 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն

3.25 (dd, ²J ϭ 9.1 Hz, ³J ϭ 4.4 Hz, 1 H, OCH₂), 3.39 (dsept, 90%. Ϫ [α]²_D⁵ϭ Ϫ432.3 (CHCl₃, c ϭ 0.55). Ϫ M.p.: 89 °C. Ϫ IR

²J_HPϭ 16.1 Hz, ³J ϭ 7.4 Hz, 1 H, PCH), 3.44 (td, ³J ϭ 2.5 Hz,

(KBr): ν˜ ϭ 3106 cm^Ϫ1, 3080, 2965, 2915, 2869, 2828, 2733, 2252,

⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 3.72 (m, 1 H, NCH₂), 4.18 (s, 5 H, 1736, 1719, 1701, 1665, 1636, 1572, 1511, 1474, 1448, 1389, 1353,

3

4

C₅H₅), 4.24 (td, J ϭ 2.7 Hz, J_HPϭ 1.0 Hz, 1 H, C₅H₃R₂), 4.60 1331, 1277, 1245, 1191, 1122, 1104, 1047, 1000, 969, 943, 913, 902,

(m, 1 H, SCH), 4.98 (m, 1 H, C₅H₃R₂). Ϫ ¹³C NMR (75 MHz,

815, 757, 717, 686, 668, 626, 594, 517, 500, 486, 460. Ϫ H NMR

1

C₆D₆): δ ϭ 14.1, 16.2 (CH₃), 18.0, 18.9 (d, ²J_CPϭ 1.8 Hz), 19.1 (d, (300 MHz, C₆D₆): δ ϭ1.22 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃),

2

²J_CP

ϭ

1.9 Hz), 19.6 (d, J_CP

ϭ

1.8 Hz, PCHCH₃), 23.3 1.59Ϫ1.86 (m, 3 H), 1.94Ϫ2.12 (m, 3 H, CH₂CH₃, β-ring-CH₂),

(NCH₂CH₂), 24.3 (d, J_CPϭ 27.4 Hz), 24.7 (d, J_CPϭ 26.2 Hz, 1.87 (s, 3 H), 2.10 (s, 3 H, SCH₃), 2.58 (td, ²J ϭ 9.1 Hz, ³J ϭ

1

Eur. J. Org. Chem. 2000, 3399Ϫ3426 3415

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

7.7 Hz, 1 H, NCH₂), 3.08 (ddd, ²J ϭ 9.1 Hz, ³J ϭ 7.4 Hz, ³J ϭ chromatography through silica gel (hexane/diethyl ether ϭ 4:1) pro-

2

4.4 Hz, 1 H, NCH₂), 3.18 (s, 3 H, OCH₃), 3.40 (dd, J ϭ 9.1 Hz, vided hydrazone 4l. Ϫ Yield: 671 mg (98%, yellow-brown powder).

³J ϭ 7.2 Hz, 1 H, OCH₂), 3.72 (dd, ²J ϭ 8.8 Hz, ³J ϭ 3.8 Hz, 1

Ϫ R_fϭ 0.70 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵

ϭ

3

H, OCH₂), 3.79 (qd, J ϭ 7.1 Hz, J ϭ 3.8 Hz, 1 H, NCH), 3.99

Ϫ440.0 (CHCl₃, c ϭ 0.21). Ϫ M.p.: 145 °C. Ϫ IR (KBr): ν˜ ϭ 3101

3

(t, J ϭ 2.7 Hz, 1 H, C₅H₃R₂), 4.04 (s, 5 H, C₅H₅), 4.20 (dd, J ϭ cm^Ϫ1, 3065, 2958, 2923, 2866, 2242, 1876, 1656, 1572, 1473, 1448,

4

3

2.5 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.66 (dd, J ϭ 10.7 Hz, J ϭ

1409, 1377, 1330, 1275, 1246, 1198, 1179, 1155, 1125, 1107, 1065,

4.7 Hz, 1 H, SCH), 4.70 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ 1.4 Hz, 1 H, 1049, 1021, 1000, 973, 932, 904, 828, 813, 743, 693, 665, 633, 591,

C₅H₃R₂). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.8, 15.1, 17.4 499, 479. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 1.07 (d, ³J ϭ 6.9 Hz,

3

(CH₃), 22.6 (NCH₂CH₂), 26.6, 27.2 (NCHCH₂, CH₂CH₃), 47.6

3 H, CHCH₃), 1.27 (t, J ϭ 7.2 Hz, 3 H, CH₂CH₃), 1.29 (d, J ϭ

(SCH), 56.9 (NCH₂), 58.7 (OCH₃), 66.6, 66.8, 67.1, 69.8 (NCH, 6.6 Hz, 3 H, CHCH₃), 1.60Ϫ1.85 (m, 3 H), 2.00Ϫ2.15 (m, 3 H, β-

C₅H₃R₂), 71.6 (C₅H₅), 75.6 (OCH₂), 79.0, 91.1 (C₅H₃R₂), 164.8 ring-CH₂, CH₂CH₃), 2.59 (td, ^2/3J ϭ 9.1 Hz, ³J ϭ 8.0 Hz, 1 H,

2

(CϭN). Ϫ EI-MS; m/z: 460.0 (100) [M^ϩ], 413.0 (11) [M^ϩϪ SCH₃],

NCH₂), 2.82 [sept, ³J ϭ 6.6 Hz, 1 H, SCH(CH₃)₂], 3.15 (ddd, J ϭ

8.5 Hz, ³J ϭ 7.8 Hz, ³J ϭ 4.4 Hz, 1 H, NCH₂), 3.23 (s, 3 H, OCH₃),

3.48 (dd, ²J ϭ 9.1 Hz, ³J ϭ 7.2 Hz, 1 H, OCH₂), 3.82 (dd, ²J ϭ

381.0 (22), 366.9 (11) [413.0 Ϫ H₂CϭS], 345.9 (21) [M^ϩ

Ϫ

C₆H₁₂NO], 299.9 (11) [345.9 Ϫ H₂CϭS], 298.9 (10) [345.9 Ϫ

H₃CS], 297.9 (23) [345.9 Ϫ H₃CSH], 284.9 (22), 282.9 (28), 268.0 9.1 Hz, ³J ϭ 3.9 Hz, 1 H, OCH₂), 3.88 (qd, ³J ϭ 8.5 Hz, ³J ϭ

(19), 256.9 (23) [H₃CSϪC₁₀H₈FeϪCN^ϩ], 246.9 (15), 241.9 (14), 3.8 Hz, 1 H, NCH), 3.93 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 3.97 (dd,

3

210.9 (11) [FcCN^ϩ], 184.9 (15) [Fc^ϩ], 170.0 (13), 156.0 (53), 120.9 ³J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.02 (s, 5 H, C₅H₅), 4.62

4

(30) [CpFe^ϩ], 89.0 (29). Ϫ C₂₂H₃₂FeN₂OS₂(460.5): calcd. C 57.38, (dd, ³J ϭ 11.4 Hz, ³J ϭ 3.5 Hz, 1 H, NϭCCH), 4.76 (dd, ³J ϭ 2.5,

H 7.00, N 6.08; found C 57.33, H 6.90, N 6.01.

⁴J ϭ 1.4, 1 H, C₅H₃R₂), 7.07 (m, 2 H, C₆H₅), 7.50 (m, 1 H, p-

C₆H₅), 7.78 (m, 2 H, C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ

13.8, 23.5, 24.5 (CH₃), 20.9 (NCH₂CH₂), 27.3 (CH₂CH₃,

NCHCH₂), 35.9, 45.0 (SCH), 57.1 (NCH₂), 58.8 (OCH₃), 67.0,

67.8, 69.7, 70.1 (NCH, C₅H₃R₂), 72.1 (C₅H₅), 75.7 (OCH₂), 78.1,

84.1 (i-C₅H₃R₂), 129.2, 136.7 (o/m-C₆H₅), 129.4 (i-C₆H₅), 131.6 (p-

C₆H₅), 166.7 (CϭN). Ϫ EI-MS; m/z: 598.0 (67) [M^ϩ], 407.8 (27)

[M^ϩϪ C₆H₁₂NO Ϫ SCH(CH₃)₂], 366.8 (12) [M^ϩϪ PhSe Ϫ Sϭ

C(CH₃)₂], 326.9 (25) [M^ϩϪ PhSe Ϫ C₆H₁₂NO], 284.8 (36) [326.9

Ϫ CH(CH₃)₂], 252.9 (11) [326.9 Ϫ SCH(CH₃)₂], 245.0 (13), 210.9

(12) [FcCN^ϩ], 184.9 (26) [Fc^ϩ], 156.0 (100) [C₆H₄Se^ϩ], 120.9 (21)

[CpFe^ϩ], 117.0 (31), 75.0 (19) [SCH(CH₃)₂^ϩ]. Ϫ C₂₉H₃₈FeN₂OSSe

(597.5): calcd. C 58.30, H 6.41, N 4.69; found C 57.97, H 6.37,

N 4.52.

Planar Chiral SAMP-hydrazone 4k: According to GP4, a solution

of hydrazone 3h (697 mg, 1.58 mmol) and LiClO₄(3.0 equiv.) in

THF (8 mL) was first treated with tBuLi (1.1 equiv.) and after-

wards with a solution of di-p-tolyl disulfide (600 mg, 1.7 equiv.) in

THF (3 mL). Aqueous work up and purification by flash chroma-

tography through silica gel (hexane/diethyl ether ϭ 4:1) provided

hydrazone 4k. Ϫ Yield: 792 mg (89%, orange crystals). Ϫ R_fϭ 0.69

(hexane/diethyl ether ϭ 4:1). Ϫ de Ն 90%. Ϫ [α]²_D⁵ϭ Ϫ219.7

(CHCl₃, c ϭ 0.84). Ϫ Mp: 105 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3017 cm^Ϫ1

,

2960, 2923, 2868, 2827, 2732, 1631, 1596, 1491, 1451, 1382, 1331,

1304, 1274, 1244, 1199, 1182, 1108, 1050, 1017, 1002, 971, 944,

909, 806, 636, 486. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 1.05 (d,

3

³J ϭ 6.7 Hz, 3 H, CHCH₃), 1.24 (t, J ϭ 7.4 Hz, 3 H, CH₂CH₃),

1.29 (d, ³J ϭ 6.4 Hz, 3 H, CHCH₃), 1.52Ϫ2.07 (m, 6 H, β-ring-

CH₂, CH₂CH₃), 2.03 (s, 3 H, C₆H₄CH₃), 2.58 (td, ^2/3J ϭ 9.1 Hz,

³J ϭ 7.7 Hz, 1 H, NCH₂), 2.85 (sept, ³J ϭ 6.7 Hz, 1 H,

SCH(CH₃)₂), 3.15 (m, 1 H, NCH₂), 3.20 (s, 3 H, OCH₃), 3.40 (dd,

Planar Chiral SAMP-hydrazone 4m: According to GP4, a solution

of hydrazone 3j (373 mg, 0.739 mmol) and LiClO₄(3.0 equiv.) in

THF (10 mL) was first treated with tBuLi (1.3 equiv.) and after-

wards with dimethyl disulfide (1.5 equiv.) in THF (3 mL). Aqueous

work up and purification by flash chromatography through silica

gel (hexane/diethyl ether ϭ 4:1) provided hydrazone 4m. Ϫ Yield:

792 mg (89%, orange crystals). Ϫ Yield: 114 mg (28%, red oil). Ϫ

3

²J ϭ 9.7 Hz, J ϭ 8.4 Hz, 1 H, OCH₂), 3.72 (m, 1 H, NCH), 3.73

2

3

(dd, J ϭ 10.1 Hz, J ϭ 3.7 Hz, 1 H, OCH₂), 3.97 (t, J ϭ 2.7 Hz,

1 H, C₅H₃R₂), 4.12 (s, 5 H, C₅H₅), 4.24 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ

R_fϭ 0.61 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 90%. Ϫ [α]²_D⁵

ϭ

3

1.4 Hz, 1 H, C₅H₃R₂), 4.58 (dd, J ϭ 10.1 Hz, J ϭ 4.7 Hz, 1 H,

Ϫ44.2 (CHCl₃, c ϭ 0.78). Ϫ IR (CHCl₃): ν˜ ϭ 3096 cm^Ϫ1, 2970,

2920, 2870, 2829, 2733, 1598, 1582, 1492, 1461, 1447, 1384, 1365,

1353, 1334, 1314, 1277, 1240, 1217, 1200, 1184, 1164, 1107, 1050,

1019, 1002, 969, 924, 813, 757, 709, 667, 497, 454. Ϫ ¹H NMR

(400 MHz, C₆D₆): δ ϭ 1.32 (d, ³J ϭ 6.6 Hz, 3 H, CHCH₃),

1.75Ϫ2.60 (m, 7 H, β-ring-CH₂, NCH₂, CH(CH₃)₂), 2.03 (s, 3 H),

NϭCCH), 4.61 (dd, ³J ϭ 2.7 Hz, J ϭ 1.3 Hz, 1 H, C₅H₃R₂), 6.88

4

3

(dm, J ϭ 8.4 Hz, 2 H, C₆H₄), 7.42 (dm, J ϭ 8.1 Hz, 2 H, C₆H₄).

Ϫ

¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.7, 20.9, 23.5, 24.6 (CH₃),

22.8 (NCH₂CH₂), 27.26, 27.31 (NCHCH₂, CH₂CH₃), 35.8, 45.6

(SCH), 57.0 (NCH₂), 58.8 (OCH₃), 67.4, 67.8, 69.7, 72.6 (NCH,

C₅H₃R₂), 72.1 (C₅H₅), 75.7 (OCH₂), 81.1, 86.6 (i-C₅H₃R₂), 129.8,

130.8 (C₆H₄), 135.8, 136.4 (i-C₆H₄), 165.5 (CϭN). Ϫ EI-MS; m/z:

3

2.05 (d, J ϭ 6.0 Hz, 3 H, CHCH₃), 2.09 (s, 3 H, SCH₃, ArCH₃),

2.82 (br., 1 H, SCH), 3.18 (s, 3 H, OCH₃), 3.52 (qd, 1 H, ³J ϭ

564.1 (80) [M^ϩ], 489.0 (18) [M^ϩϪ SCH(CH₃)₂], 488.0 (28) [M^ϩ

HSCH(CH₃)₂], 443.0 (15) [488.0 Ϫ CH₂OCH₃], 376.0 (20) [M^ϩ

Ϫ

3

2

3

7.2 Hz, J ϭ 4.1 Hz, NCH), 3.58 (dd, J ϭ 8.8 Hz, J ϭ 4.4 Hz, 1

Ϫ

H, OCH₂), 4.03 (t, ³J ϭ 2.6 Hz, 1 H, C₅H₃R₂), 4.13 (s, 5 H, C₅H₅),

C₅H₅Ϫ SC₇H₇], 375.1 (19), 374.0 (41) [488.0 Ϫ C₆H₁₂NO], 332.8

(34), 307.8 (19) [FcϪSϪC₇H₇^ϩ], 284.9 (23), 244.0 (15), 241.9 (15),

211.0 (15) [FcCN^ϩ], 184.9 (26) [Fc^ϩ], 156.0 (100) [FcCNH^ϩϪ Fe],

151.0 (15), 120.9 (69) [CpFe^ϩ], 117.0 (34), 91.0 (28) [C₇H₇^ϩ], 76.1

(97), 75.1 (41) [SCH(CH₃)₂], 74.1 (61), 73.1 (15), 70.1 (25), 61.1

(60), 59.1 (82), 58.2 (20), 47.2 (19), 45.3 (77) [CH₃OCH₂^ϩ]. Ϫ

C₃₀H₄₀FeN₂OS₂(564.6): calcd. C 63.82, H 7.14, N 4.96; found C

64.00, H 7.19, N 4.81.

3

4

3

4.28 (dd, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.40 (dd, J ϭ

2.6 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 6.89 (dm, ³J ϭ 7.7 Hz, 2 H,

C₆H₄), 7.44 (dm, ³J ϭ 8.2 Hz, 2 H, C₆H₄). Ϫ ¹³C NMR (100 MHz,

C₆D₆): δ ϭ 20.9, 22.1, 22.4, 32.8 (CH₃), 22.8 (NCH₂CH₂), 27.6

(NCHCH₂), 56.1, 58.8 (NCH, OCH₃), 57.2 (NCH₂), 67.1, 67.5,

68.5 (C₅H₃R₂), 70.5 (SCH), 71.7 (C₅H₅), 75.5 (OCH₂), 129.7, 129.9

(C₆H₄), 131.0, 131.7, 136.2 (CϭN, i-C₆H₄). Ϫ EI-MS; m/z: 550.1

(43) [M^ϩ], 472.0 (100) [M^ϩϪ SC₇H₇], 426.1 (25) [M^ϩϪ HSC₇H₇],

381.1 (28) [427.0 Ϫ SϭCH₂], 314.0 (46) [427.0 Ϫ C₆H₁₂NO], 311.9

(33) [426.1 Ϫ C₆H₁₂NO], 298.9 (44) [314.0 Ϫ CH₃], 296.9 (32)

[311.9 Ϫ CH₃], 268.0 (18) [314.0 Ϫ H₂CϭS], 264.9 (28) [311.9 Ϫ

Planar Chiral SAMP-hydrazone 4l: According to GP4, a solution

of hydrazone 3h (508 mg, 1.15 mmol) and LiClO₄(3.0 equiv.) in

THF (6 mL) was first treated with tBuLi (1.2 equiv.) and after-

wards with a solution of phenyl selenenyl bromide (461 mg, 1.7 H₃CS], 256.9 (15) [H₃CSC₁₀H₈FeCN^ϩ], 241.9 (11), 230.9 (13),

equiv.) in THF (1 mL). Aqueous work up and purification by flash

3416

213.5 (16), 210.9 (11) [FcCN^ϩ], 185.9 (12) [Cp₂Fe^ϩ], 184.9 (14)

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

[Fc^ϩ], 179.0 (11) [(H₃C)₂CHCHSC₇H₇^ϩ], 170.1 (81), 124.0 (16) work up and purification by flash chromatography through silica

[HSC₇H₇^ϩ], 122.9 (15) [SC₇H₇^ϩ], 120.9 (28) [CpFe^ϩ], 91.0 (22) gel (hexane/diethyl ether ϭ 4:1) provided hydrazine 5a. Ϫ Yield:

[C₇H₇^ϩ]. Ϫ C₂₉H₃₈FeN₂OS₂(550.6): calcd. C 63.26, H 6.96, N

5.09; found C 63.37, H 7.09, N 5.39.

93 mg (93%, yellow oil). Ϫ R_fϭ 0.61 (hexane/diethyl ether ϭ 4:1).

Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ164.8 (CHCl₃, c ϭ 0.65). Ϫ IR (CHCl₃):

ν˜ ϭ 3092 cm^Ϫ1, 2963, 2922, 2873, 2828, 1724, 1671, 1583, 1550,

1447, 1383, 1279, 1197, 1106, 1041, 1001, 960, 878, 816, 755, 715,

690, 665, 489. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 1.10 (t, ³J ϭ

7.2 Hz, 3 H, CH₂CH₃), 1.48Ϫ1.94 (m, 6 H, CH₂CH₃, β-ring-CH₂),

1.66 (s, 3 H, SCH₃), 1.99 (dt, ²J ϭ 9.4 Hz, ³J ϭ 8.1 Hz, 1 H,

Planar Chiral SAMP-hydrazone 4n: According to GP4, a solution

of hydrazone 3c (530 mg, 0.96 mmol) and LiClO₄(5.0 equiv.) in

THF (20 mL) was first treated with tBuLi (2.5 equiv.) and after-

wards with a solution of 1,2-diiodoethane (730 mg, 2.7 equiv.) in

THF (1 mL). Aqueous work up and purification by flash chroma-

tography through silica gel (hexane/diethyl ether ϭ 4:1) provided

hydrazone 4n. Ϫ Yield: 792 mg (89%, orange crystals). Ϫ Yield:

288 mg (44%, orange-brown crystals). Ϫ R_fϭ 0.40 (hexane/diethyl

ether ϭ 4:1). Ϫ (E)/(Z) ϭ 11.7:1. Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ12.8

3

NCH₂), 2.34 (s, 3 H, CpCH₃), 2.76 (qd, J ϭ 8.1 Hz, J ϭ 3.4 Hz,

1 H, NCH_ring), 3.00 (broad s, 1 H, NH), 3.31 (s, 3 H, OCH₃), 3.35

(ddd, ²J ϭ 8.7 Hz, ³J ϭ 6.4 Hz, ³J ϭ 2.4 Hz, 1 H, NCH₂), 3.41

3

2

(td, J ϭ 8.1 Hz, J ϭ 2.4 Hz, 1 H, SCH), 3.58 (dd, J ϭ 8.7 Hz,

³J ϭ 6.7 Hz, 1 H, OCH₂), 3.87 (m, 1 H, C₅H₃R₂), 3.90 (m, 2 H,

C₅H₃R₂), 3.92 (dd, ²J ϭ 9.1 Hz, ³J ϭ 3.7 Hz, 1 H, OCH₂), 4.02 (d,

³J ϭ 7.1 Hz, CpCHN), 4.03 (s, 5 H, C₅H₅). Ϫ ¹³C NMR (75 MHz,

C₆D₆): δ ϭ 12.9, 13.0, 16.1 (CH₃), 21.4 (NCH₂CH₂), 25.3, 26.7

(CH₂CH₃, NCHCH₂), 52.0 (SCH), 56.4 (NCH₂), 59.0 (OCH₃),

63.8 (FcCH), 66.39, 66.45, 69.2, 71.1 (C₅H₃R₂, NCH_ring), 69.5

(C₅H₅), 75.3 (OCH₂), 84.0, 87.3 (i-C₅H₃R₂). Ϫ EI-MS; m/z: 430.1

(CHCl₃, c ϭ 0.47). Ϫ M.p.: 68 °C. Ϫ IR (KBr): ν˜ ϭ 3080 cm^Ϫ1

,

3055, 2969, 2926, 2871, 2827, 2380, 2346, 2265, 1737, 1655, 1638,

1577, 1482, 1437, 1376, 1308, 1275, 1241, 1187, 1106, 1062, 1001,

969, 890, 818, 739, 697, 655, 608, 558, 498. Ϫ ¹H NMR (300 MHz,

C₆D₆): δ ϭ 1.56Ϫ1.82 (m, 3 H), 2.06 (m, 1 H, β-ring-CH₂), 1.63

3

(dd, J_HPϭ 16.2 Hz, J ϭ 7.7 Hz, 3 H, CHCH₃), 2.39 (td, ^2/3J ϭ

3

9.1 Hz, J ϭ 7.7 Hz, 1 H, NCH₂), 3.09 (m, 1 H, NCH₂), 3.29 (s, 3

H, OCH₃), 3.51 (dd, J ϭ 9.9 Hz, J ϭ 8.3 Hz, 1 H, OCH₂), 3.73

(m, 2 H, OCH₂, NCH), 3.91 (t, J ϭ 2.7 Hz, 1 H, C₅H₃R₂), 3.93

(4) [M^ϩ], 428.1 (18) [M^ϩ

Ϫ Ϫ

H₂], 341.1 (11) [M^ϩ

2

3

H₃CSCHCH₂CH₃], 340.1 (13) [M^ϩϪ H₃CSCH₂CH₂CH₃], 301.1

(26) [M^ϩϪ C₆H₁₃N₂O], 300.0 (35) [M^ϩϪ C₆H₁₄N₂O], 268.1 (12),

265.9 (15) [M^ϩϪ C₆H₁₂NO Ϫ H₂Ϫ H₃CSH], 255.1 (19) [300.0 Ϫ

CH₂OCH₃], 254.0 (100) [300.0 Ϫ H₂CϭS], 252.1 (15), 227.1 (12),

226.0 (41), 225.0 (25) [C₁₀H₈FeCH₃CN^ϩ], 224.1 (12), 200.0 (15),

198.9 (40) [C₁₀H₈FeCH₃^ϩ], 134.0 (10), 129.1 (12) [C₁₀H₉^ϩ], 121.0

(41) [CpFe^ϩ], 114.9 (12), 91.1 (13) [H₃CSHCH₂CH₂CH₃^ϩ], 89.0

(20) [H₃CSCHCH₂CH₃^ϩ], 56.1 (44) [Fe^ϩ], 45.3 (12) [CH₂OCH₃^ϩ].

3

4

(s, 5 H, C₅H₅), 4.30 (dd, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂),

4.71 (dd, ³J ϭ 2.8 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 5.02 (dq, ²J_HPϭ

3

15.7 Hz, J ϭ 7.7 Hz, 1 H, PCH), 7.05 (m, 6 H, m/p-C₆H₅), 7.81

(ddd, J_HPϭ 9.6 Hz, ³J ϭ 8.2 Hz, ⁴J ϭ 1.7 Hz, 2 H, o-C₆H₅), 8.11

3

4

(ddd, J_HPϭ 9.9 Hz, J ϭ 8.5 Hz, J ϭ 1.7 Hz, 2 H, o-C₆H₅). Ϫ

¹³C NMR (75 MHz, C₆D₆): δ ϭ 14.8 (d, ²J_CPϭ 4.0 Hz, CH₃), 22.5

(NCH₂CH₂), 26.7 (NCHCH₂), 32.4 (d, ¹J_CPϭ 30.4 Hz, PCH), 56.4

(NCH₂), 58.6 (OCH₃), 67.1, 68.4, 69.1, 76.8 (NCH, C₅H₃R₂), 72.8

Ϫ

HR-MS: C₂₂H₃₂⁵⁶FeN₂OS: calcd. 428.158472; found

428.158450.

3

(i-C₆H₅), 75.4 (OCH₂), 80.8 (i-C₆H₅), 128.1 (d, J_CPϭ 10.3 Hz),

128.3 (d, ³J_CPϭ 9.8 Hz, m-C₆H₅), 130.5, 130.6 (p-C₆H₅), 132.6 (d,

²J_CPϭ 8.6 Hz), 133.1 (d, ²J_CPϭ 9.2 Hz, o-C₆H₅), 161.1 (CϭN). Ϫ

³¹P NMR (C₆D₆, 162 MHz): ϩ24.8 (broad). Ϫ EI-MS; m/z: 424.2

(32) [M^ϩϪ Ph₂PϪBH₃Ϫ Fe], 416.2 (27), 371.2 (38), 303.2 (16),

185.1 (100) [PPh₂^ϩ], 183.1 (36) [185.1 Ϫ H₂], 66.2 (27) [C₅H₆^ϩ]. Ϫ

C₃₁H₃₇BFeIN₂OP (678.2): calcd. C 54.90, H 5.50, N 4.13; found C

55.44, H 5.74, N 3.89.

Hydrazine 5b: According to GP5, a solution of hydrazone 4f

(441 mg, 0.737 mmol) in diethyl ether/CH₂Cl₂(2:1, 30 mL) was

treated with catecholborane (8.0 equiv.) at Ϫ40 °C. After warming

to room temperature, the reaction mixture was stirred for 72 h at

room temperature. Aqueous work up and purification by flash

chromatography through silica gel (hexane/diethyl ether ϭ 4:1) pro-

vided hydrazine 5b. Ϫ Yield: 173 mg (39%, yellow crystals). Ϫ R_fϭ

0.21 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ174.4

General Procedure for the Preparation of Hydrazines 5 (GP5): The

hydrazones 4 bearing a Ph₂PBH₃group in the side chain, were

deprotected first by stirring with TMEDA (5 equiv.) in dry diethyl

ether for several hours. Since deprotected phosphanes 4 are ex-

tremely sensitive to oxidation, all synthetic manipulations were car-

ried out with rigorous exclusion of oxygen. The solution was

washed three times with saturated aqueous NH₄Cl, once with brine

and dried with MgSO₄. The crude product was filtered under argon

through silica gel and then dried under high vacuum for several

hours. The hydrazones 4 were dissolved in CH₂Cl₂/diethyl ether

(1:1 to 1:2) and cooled to Ϫ20 °C. To the solution, freshly distilled

catecholborane (5Ϫ8 equiv.) was added dropwise with vigorous

stirring, and the reaction mixture was warmed to room temper-

ature. After completion of the reaction (TLC control with ninhyd-

rin: hydrazones purple, hydrazines orange), the reaction was

quenched at 0 °C with saturated aqueous NH₄Cl, washed twice

with saturated aqueous K₂CO₃, once with brine, and dried with

MgSO₄. The crude product was purified by flash chromatography

(hexane/ether ϭ 4:1 to 10:1). Hydrazines bearing an R₂P group in

the side chain, are protected with BH₃DMS prior to workup (2 h,

0 °C).

(CHCl₃, c ϭ 0.61). Ϫ M.p.: 74 °C. Ϫ IR (KBr): ν˜ ϭ 3078 cm^Ϫ1

,

3055, 2959, 2917, 2871, 2824, 2389, 2346, 2260, 2202, 1737, 1719,

1703, 1654, 1637, 1564, 1545, 1481, 1459, 1436, 1384, 1312, 1265,

1237, 1186, 1160, 1105, 1061, 1002, 954, 917, 822, 741, 698, 631,

1

609, 505, 479. Ϫ H NMR (500 MHz, C₆D₆): δ ϭ 1.51 (m, 1 H,

NCH₂CH₂), 1.52 (d, ³J ϭ 7.0 Hz, 3 H, CHCH₃), 1.57 (s, 3 H,

SCH₃), 1.62 (m, 1 H, NCH₂CH₂), 1.71 (m, 1 H, NCHCH₂), 1.95

2

(dddd, J ϭ 15.6 Hz, ³J ϭ 12.5 Hz, ³J ϭ 9.8 Hz, ³J ϭ 5.9 Hz, 1 H,

2

NCHCH₂), [¹¹B-decoupling: 2.26 (d, J_HPϭ 14.6 Hz, 3 H, BH₃)],

2.56 (qd, ³J ϭ 5.1 Hz, ³J ϭ 1.9 Hz, 1 H, SCH), 2.59 (td, ^2/3J ϭ

8.6 Hz, ³J ϭ 7.7 Hz, 1 H, NCH₂), 2.92 (qd, ³J ϭ 8.5 Hz, ³J ϭ

3.7 Hz, 1 H, NCH), 3.18 (broad, 1 H, NH), 3.37 (s, 3 H, OCH₃),

3.53 (ddd, ²J ϭ 8.6 Hz, ³J ϭ 7.4 Hz, ³J ϭ 3.7 Hz, 1 H, NCH₂),

3.66 (dd, ²J ϭ 8.9 Hz, ³J ϭ 7.0 Hz, 1 H, OCH₂), 3.86 (td, ³J ϭ

³J_HPϭ 2.4 Hz, ⁴J ϭ 1.5 Hz, 1 H, PC-CH_Cp), 4.00 (dd, ²J ϭ 8.9 Hz,

³J

ϭ 3.8 Hz, 1 ϭ 2.5 Hz, 1 H,

H, OCH₂), 4.14 (t, ³J

3

PCϪCHϪCH_Cp), 4.26 (s, 5 H, C₅H₅), 4.94 (d, J ϭ 1.7 Hz, 1 H,

FcCH), 5.07 (dt, ³J ϭ 2.5 Hz, ⁴J ϭ J_HPϭ 1.8 Hz, 1 H, PC-

4

3

(CH)₂ϪCH_Cp), 6.93Ϫ7.05 (m, 6 H, m/p-C₆H₅), 7.76 (ddd, J_HP

ϭ

10.5 Hz, ³J ϭ 7.7 Hz, ⁴J ϭ 1.5 Hz, 2 H, o-C₆H_5ax), 7.85 (ddd,

³J_HPϭ 10.5 Hz, J ϭ 7.9 Hz, J ϭ 1.5 Hz, 2 H, o-C₆H_5eq). Ϫ ¹³C

3

4

Hydrazine 5a: According to GP5, a solution of hydrazone 4j

(100 mg, 0.233 mmol) in CH₂Cl₂(20 mL) was treated with catech-

olborane (5.0 equiv.) at Ϫ40 °C. After warming to 10 °C, aqueous

NMR (75 MHz, C₆D₆): δ ϭ 13.8 (SCH₃), 19.4 (CHCH₃), 20.9

(NCH₂CH₂), 27.4 (NCHCH₂), 49.9 (SCH), 56.7 (NCH₂), 58.5

3

(FcCH, OCH₃), 66.0 (NCH), 69.4 (d, J_CP

ϭ

5.7 Hz,

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3417

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

3

PCϪCHϪCH_Cp), 70.4 (C₅H₅), 72.3 (d, ²J_CPϭ 2.8 Hz, PCϪCH_Cp),

1.15 (dd, J_HPϭ 14.4 Hz, J ϭ 7.1 Hz, 3 H, PCHCH₃), 1.20 (dd,

72.5 (d, J_CPϭ 8.1 Hz, PC-(CH)₂ϪCH_Cp), 75.7 (OCH₂), 96.7 (d, ³J_HPϭ 14.8 Hz, ³J ϭ 7.4 Hz, 3 H, PCHCH₃), 1.21 (t, ³J ϭ 6.7 Hz,

3

¹J_CPϭ 15.5 Hz, PC_Cp), 127.7 (d, J_CPϭ 8.0 Hz, m-C₆H₅), 128.0 3 H, CH₂CH₃), 1.42 (dd, J_HPϭ 15.1 Hz, ³J ϭ 7.1 Hz, 3 H,

3

4

(d, J_CPϭ 9.6 Hz, m-C₆H₅), 130.3 (d, J_CPϭ 2.3 Hz, p-C₆H₅),

PCHCH₃), 1.55Ϫ1.96 (m, 5 H), 2.14Ϫ2.36 (m, 2 H, β-ring-CH₂,

1

2

131.2 (d, J_CPϭ 57.1 Hz, i-C₆H₅), 132.1 (d, J_CPϭ 42.9 Hz, i- CH₂CH₃, PCH), 1.86 (s, 3 H, SCH₃), 2.51 (dsept, J_HPϭ 12.8 Hz,

C₆H₅), 132.5 (d, ²J_CPϭ 9.1 Hz, o-C₆H_5ax), 133.3 (d, ²J_CPϭ 9.8 Hz, ³J ϭ 7.4 Hz, 1 H, PCH), 2.68 (ddd, ³J ϭ 10.4 Hz, ³J ϭ 4.4 Hz,

o-C₆H_5eq). Ϫ ³¹P NMR (C₆D₆, 162 MHz): ϩ15.5 (broad). Ϫ ¹¹B

³J ϭ 1.3 Hz, 1H, SCH), 3.08Ϫ3.18 (m, 3H), 3.65 (m, 1H, NH,

NMR (C₆D₆, 160 MHz): Ϫ36.1 (broad). Ϫ EI-MS; m/z: 586.1 (13) NCH, NCH₂), 3.27 (s, 3 H, OCH₃), 3.61 (dd, ²J ϭ 9.1 Hz, ³J ϭ

[M^ϩϪ BH₃], 511.0 (98) [586.1 Ϫ H₃CSCHCH₃], 457.0 (69) [M^ϩ3.7 Hz, 1H, OCH₂), 3.71 (dd, ²J ϭ 9.1 Hz, ³J ϭ 5.7 Hz, 1 H,

Ϫ ΗNNC₆H₁₂O], 395.9 (100) [511.0 Ϫ C₆H₁₃NO], 289.0 (44), 132.9

OCH₂), 4.10 (t, ³J ϭ 2.7 Hz, 1 H, C₅H₃R₂), 4.26 (m, 1 H, C₅H₃R₂),

(60), 121.0 (31) [CpFe^ϩ], 91.1 (61), 83.1 (37).

Ϫ

HR-MS: 4.30 (s, 5 H, C₅H₅), 4.39 (broad d, J ϭ 1.3 Hz, 1 H, FcCH), 4.93

3

C₃₂H₃₉⁵⁶FeN₂OPS (M^ϩ

586.186785.

Ϫ

BH₃): calcd. 586.187012; found

(dt, ³J ϭ 2.4 Hz, ⁴J ϭ 1.3 Hz, 1 H, C₅H₃R₂). Ϫ ¹³C NMR

(75 MHz, C₆D₆): δ ϭ 13.8 (CH₂CH₃), 17.0 (SCH₃), 17.1 (d, ²J_CPϭ

2.4), 18.9 (broad), 19.1 (broad), 19.6 (PCHCH₃), 22.3 (NCH₂CH₂),

1

Hydrazine 5c: According to GP5, a solution of hydrazone 4g

(56 mg, 0.085 mmol) in diethyl ether/CH₂Cl₂(2:1, 7.5 mL) was

treated with catecholborane (8.0 equiv.) at Ϫ40 °C. After warming

to room temperature, the reaction mixture was stirred for 72 h at

room temperature. Aqueous work up and purification by flash

chromatography through silica gel (hexane/diethyl ether ϭ 4:1) pro-

vided hydrazine 5c. Ϫ Yield: 43 mg (82%, yellow oil). Ϫ R_fϭ 0.37

(hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ154.2

(CHCl₃, c ϭ 0.67). Ϫ IR (CHCl₃): ν˜ ϭ 3078 cm^Ϫ1, 3058, 3006,

2963, 2923, 2872, 2830, 2396, 2353, 2264, 1483, 1462, 1437, 1384,

1337, 1313, 1289, 1217, 1200, 1187, 1163, 1106, 1062, 1029, 1002,

966, 921, 823, 737, 699, 667, 632, 613, 506, 479. Ϫ ¹H NMR

(300 MHz, C₆D₆): δ ϭ 0.88 (t, ³J ϭ 7.2 Hz, 3 H, CH₂CH₃),

1.49Ϫ2.00 (m, 6 H, β-ring-CH₂, CH₂CH₃), 1.55 (s, 1 H, NH), 1.71

24.4 (d, J_CPϭ 33.0 Hz), 25.4 (d, J_CPϭ 33.6 Hz, PCH), 27.6

(NCHCH₂), 28.4 (CH₂CH₃), 56.8 (NCH₂), 58.3, 58.9, 59.0 (FcCH,

SCH, OCH₃), 65.6 (NCH), 69.6 (d, J_CPϭ 6.7), 71.6 (d, J_CPϭ 6.7),

72.7 (d, J_CPϭ 9.2, C₅H₃R₂), 71.0 (C₅H₅), 75.8 (OCH₂), 94.4 (i-

C₅H₃R₂). Ϫ ³¹P NMR (162 MHz, C₆D₆): δ ϭ ϩ33.2 (broad). Ϫ

EI-MS; m/z: 546.2 (19) [M^ϩ], 457.1 (66) [M^ϩϪ H₃CSCHCH₂CH₃],

443.1 (100) [457.1 Ϫ BH₃], 417.0 (92) [M^ϩϪ HNNC₆H₁₂O], 403.0

(29) [417.0 Ϫ BH₃], 357.0 (27) [403.0 Ϫ SϭCH₂], 342.0 (32) [457.1

Ϫ HNC₆H₁₂O], 330.0 (29), 327.9 (56) [342.0 Ϫ BH₃], 235.0 (27),

132.9 (36), 129.0 (50) [HNC₆H₁₂O]. Ϫ HR-MS: C₂₇H₄₈⁵⁶FeN₂OPS:

calcd. 546.266742; found 546.266727.

Hydrazine 5e: According to GP5, a solution of hydrazone 4i

(100 mg, 0.160 mmol) in diethyl ether/CH₂Cl₂(2:1, 15 mL) was

treated with catecholborane (8.0 equiv.) at Ϫ40 °C. After warming

to room temperature, the reaction mixture was stirred for 120 h

at room temperature. Aqueous work up and purification by flash

chromatography through silica gel (hexane/diethyl ether ϭ 7:1) pro-

vided hydrazine 5e. Ϫ Yield: 43 mg (43%, yellow-orange crystals).

2

3

(s, 3 H, SCH₃), 2.05 (dd, J ϭ 9.7 Hz, J ϭ 4.4 Hz, J ϭ 1.7 Hz,

2

3

NCH₂), 2.78 (dt, J ϭ 8.4 Hz, J ϭ 7.7 Hz, 1 H, NCH₂), 2.98 (m,

1 H, NCH), 3.42 (m, 1 H, SCH), 3.42 (s, 3 H, OCH₃), 3.69 (dd,

²J ϭ 9.1 Hz, ³J ϭ 6.7 Hz, 1 H, OCH₂), 3.80 (q, ^3/4J ϭ J_HP

ϭ

2.5 Hz, 1 H, C₅H₃R₂), 4.01 (dd, ²J ϭ 9.1 Hz, ³J ϭ 3.7 Hz, 1 H,

3

OCH₂), 4.12 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.29 (s, 5 H, C₅H₅),

Ϫ R_fϭ 0.27 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵

ϭ

4.94 (broad s, 1 H, FcCH), 5.06 (m, 1 H, C₅H₃R₂), 6.88Ϫ7.04 (m),

7.42 (ddd, J ϭ 11.4 Hz, J ϭ 8.1 Hz, J ϭ 1.7 Hz, 6 H, m/p-C₆H₅),

7.76 (m, 2 H, o-C₆H₅), 7.86 (m, 2 H, o-C₆H₅). Ϫ ¹³C NMR

(75 MHz, C₆D₆): δ ϭ 13.4, 16.6 (CH₃), 21.7 (NCH₂CH₂), 28.0,

28.9 (CH₂CH₃, NCHCH₂), 57.5 (NCH₂), 58.8 (OCH₃), 59.1

(SCH), 66.7 (NCH), 69.8, 69.9, 72.8 (C₅H₃R₂), 71.0 (C₅H₅), 76.4

(OCH₂), 97.2 (i-C₅H₃R₂), 128.5 (d, ³J_CPϭ 9.8 Hz, m-C₆H₅), 130.8,

Ϫ153.2 (CHCl₃, c ϭ 0.77). Ϫ Mp: 126 °C. Ϫ IR (KBr): ν˜ ϭ 3054

cm^Ϫ1, 2954, 2922, 2887, 2865, 2823, 2387, 2350, 2262, 1720, 1655,

1544, 1483, 1460, 1439, 1382, 1365, 1317, 1244, 1199, 1163, 1136,

1106, 827, 744, 699, 631, 611, 511, 479. Ϫ ¹H NMR (300 MHz,

3

C₆D₆): δ ϭ 0.89 [d, J ϭ 6.6 Hz, 3 H, SCH(CH₃)₂], 1.07 [d, J ϭ

6.6 Hz, 3 H, SCH(CH₃)₂], 1.56 [d, ³J ϭ 7.1 Hz, 3 H, Fc(CH)₂CH₃],

1.60Ϫ1.80 (m, 3 H, β-ring-CH₂), 1.96 (m, 2 H, β-ring-CH₂, NCH),

1

131.0 (p-C₆H₅), 131.5 (d, J_CPϭ 60.1 Hz), 132.0 (d, J_CP

ϭ

3

60.1 Hz, i-C₆H₅), 133.5 (d, ²J_CPϭ 9.2 Hz), 133.8 (d, ²J_CPϭ 9.2 Hz,

o-C₆H₅). Ϫ ³¹P NMR (C₆D₆, 162 MHz): ϩ11.9 (broad). Ϫ EI-MS;

m/z: 615.2 (39) [MH^ϩ], 614.2 (31) [M^ϩ], 613.2 (33) [M^ϩϪ H], 601.1

(25) [MH^ϩϪ BH₃], 600.1 (11) [M^ϩϪ BH₃], 583.1 (13), 418.1 (15),

417.0 (49), 416.1 (23) [MH^ϩϪ Ph₂P Ϫ BH₃], 286.9 (17), 259.0 (29),

199.0 (11) [Ph₂P-BH₂^ϩ], 187.0 (32), 128.1 (100) [C₆H₁₂N₂O^ϩ], 91.1

(16). Ϫ C₃₃H₄₄BFeN₂OPS (614.4): calcd. C 64.51, H 7.22, N 4.56;

found C 64.03, H 7.46, N 4.07.

2.50 [sept, J ϭ 6.6 Hz, 1 H, SCH(CH₃)₂], 2.65 (qd, J ϭ 7.1 Hz,

³J ϭ 1.1 Hz, 1 H, SCHCHN), 2.84 (dt, J ϭ 8.5 Hz, J ϭ 8.0 Hz,

2

3

1 H, NCH₂), 3.04 (m, 1 H, NH), 3.41 (s, 3 H, OCH₃), 3.45 (m, 1

2

3

H, NCH₂), 3.72 (dd, J ϭ 8.8 Hz, J ϭ 6.9 Hz, 1 H, OCH₂), 3.86

(q, ^3/4J ϭ J_HPϭ 1.8 Hz, 1 H, C₅H₃R₂), 4.03 (dd, ²J ϭ 8.8 Hz, ³J ϭ

3

4.0 Hz, 1 H, OCH₂), 4.12 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.23 (s, 5

H, C₅H₅), 4.89 (broad s, 1 H, FcCH), 5.02 (q, ^3/4J ϭ J_HPϭ 1.8 Hz,

1 H, C₅H₃R₂), 7.04 (m, 6 H, m/p-C₆H₅), 7.78 (ddd, J ϭ 9.9 Hz,

J ϭ 7.1 Hz, ⁴J ϭ 2.5 Hz, 2 H, o-C₆H₅), 7.87 (ddd, J ϭ 9.9 Hz, J ϭ

4

Hydrazine 5d: According to GP5, a solution of hydrazone 4h

7.2 Hz, J ϭ 1.9 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆):

(143 mg, 0.263 mmol) in diethyl ether/CH₂Cl₂(2:1, 21 mL) was

δ ϭ 21.7 (NCH₂CH₂), 22.0, 24.0, 24.4 (CH₃), 28.0 (NCHCH₂),

treated with catecholborane (8.0 equiv.) at Ϫ40 °C. After warming 34.1 [SCH(CH₃)₂], 47.4 (SCHCHN), 57.2 (NCH₂), 58.9 (OCH₃),

to room temperature, the reaction mixture was stirred for 15 h at 59.0 (d, J_CPϭ 6.8 Hz, FcCH), 66.6 (NCH), 66.9 (i-C₅H₃R₂), 70.0

room temperature. Aqueous work up and purification by flash (d, J_CPϭ 6.3 Hz), 70.9 (d, J_CPϭ 4.6 Hz), 72.7 (C₅H₃R₂), 70.8

chromatography through silica gel (hexane/diethyl ether ϭ 7:1) pro-

(C₅H₅), 76.3 (OCH₂), 97.0 (d, ¹J_CPϭ 15.5 Hz, i-C₅H₃R₂), 128.3 (d,

vided hydrazone 5d. Ϫ Yield: 78 mg (55%, yellow crystals). Ϫ R_fϭ ³J_CPϭ 9.2 Hz), 128.5 (d, ³J_CPϭ 10.3 Hz, m-C₆H₅), 130.8 (p-C₆H₅),

0.64 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 90%. Ϫ [α]²_D⁵ϭ ϩ21.5

(CHCl₃, c ϭ 0.14). Ϫ M.p.: 104 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3096 cm^Ϫ1

2963, 2927, 2873, 2734, 2384, 2269, 1726, 1503, 1462, 1384, 1365,

131.9 (d, ¹J_CPϭ 60.1 Hz), 132.3 (d, ¹J_CPϭ 56.1 Hz, i-C₆H₅), 133.2

2

,

(d, ²J_CPϭ 9.2 Hz), 133.7 (d, J_CPϭ 9.2 Hz, o-C₆H₅). Ϫ ³¹P NMR

(C₆D₆, 162 MHz): ϩ12.3 (broad). Ϫ CI-MS (isobutane); m/z: 629.3

1288, 1252, 1218, 1202, 1185, 1109, 1069, 1044, 1003, 964, 929, 885, (20) [MH^ϩ], 628.3 (17) [M^ϩ], 627.2 (16) [M^ϩϪ H], 615.2 (100)

824, 756, 689, 667, 649, 507, 494, 481. Ϫ ¹H NMR (300 MHz,

[MH^ϩϪ BH₃], 614.2 (10) [M^ϩϪ BH₃], 539.1 (14) [615.2 Ϫ HSiPr],

C₆D₆): δ ϭ 1.03 (dd, ³J_HPϭ 13.1 Hz, ³J ϭ 7.1 Hz, 3 H, PCHCH₃), 187.0 (13), 131.2 (12) [C₆H₁₅N₂O], 116.0 (29), 114.0 (34)

3418

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

[C₆H₁₂NO^ϩ]. Ϫ C₃₄H₄₆BFeN₂OPS (628.5): calcd. C 64.98, H 7.38,

N 4.46; found C 64.96, H 7.34, N 4.18.

3.14 (s, 3 H, OCH₃), 3.18 [m, 2 H, NCH₂, SCH(CH₃)₂], 3.38 (ddd,

3

³J ϭ 11.1 Hz, J ϭ 3.0 Hz, J ϭ 2.0 Hz, 1 H, SCHCH₂), 3.80 (dd,

3

²J ϭ 8.7 Hz, J ϭ 4.0 Hz, 1 H, OCH₂), 4.02 (t, J ϭ 2.7 Hz, 1 H,

2

3

Hydrazine 5f: According to GP5, a solution of hydrazone 4j

(105 mg, 0.228 mmol) in diethyl ether/CH₂Cl₂(2:1, 15 mL) was

treated with catecholborane (8.0 equiv.) at Ϫ40 °C. After warming

to room temperature, the reaction mixture was stirred for 15 h at

room temperature. Aqueous work up and purification by flash

chromatography through silica gel (hexane/diethyl ether ϭ 4:1) pro-

vided hydrazine 5f. Ϫ Yield: 79 mg (75%, orange crystals). Ϫ R_fϭ

0.30 (hexane/diethyl ether ϭ 4:1). Ϫ de ϭ 87%. Ϫ [α]²_D⁵ϭ Ϫ211.4

C₅H₃R₂), 4.13 (s, 5 H, C₅H₅), 4.13 (dd, J ϭ 8.4 Hz, J ϭ 6.7 Hz,

1 H, OCH₂), 4.35 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ 1.0 Hz, 1 H, C₅H₃R₂),

3

4

3

4.39 (dd, J ϭ 2.4 Hz, J ϭ 1.7 Hz, 1 H, C₅H₃R₂), 4.51 (d, J ϭ

2.0 Hz, 1 H, FcCH), 6.84 (dm, ³J ϭ 8.1 Hz, 2 H, C₆H₄), 7.23 (dm,

³J ϭ 8.1 Hz, 2 H, C₆H₄). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.3,

20.8 (CH₃), 21.3, 23.7 (CH₂CH₃, NCH₂CH₂), 24.1, 24.5 (CH₃),

27.5 (NCHCH₂), 36.2 (SCH(CH₃)₂), 54.1 (SCHCN), 56.5 (NCH₂),

58.8 (OCH₃), 60.6 (FcCH), 66.7, 68.8, 71.0, 74.7 (NCH, C₅H₃R₂),

70.5 (C₅H₅), 75.6 (OCH₂), 77.3, 95.5 (i-C₅H₃R₂), 127.1, 129.6

(C₆H₄) 134.9, 137.6 (i-C₆H₄). Ϫ EI-MS; m/z: 567.2 (38) [MH^ϩ],

(CHCl₃, c ϭ 0.74). Ϫ M.p.: 105 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3093 cm^Ϫ1

,

2963, 2918, 2871, 2826, 1725, 1660, 1642, 1610, 1450, 1384, 1351,

1310, 1283, 1233, 1200, 1186, 1107, 1034, 1002, 955, 921, 891, 817,

566.2 (26) [M^ϩ], 437.0 (17) [M^ϩϪ C₆H₁₃N₂O], 436.0 (12) [M^ϩ

Ϫ

1

756, 681, 574, 498. Ϫ H NMR (major isomer, 400 MHz, C₆D₆):

C₆H₁₄N₂O], 419.0 (13), 363.0 (75), 362.0 (100) [437.0

Ϫ

δ ϭ 1.26 (t, ³J ϭ 6.6 Hz, 3 H, CH₂CH₃), 1.47Ϫ1.66 (m, 4 H, β-

ring-CH₂), 1.83 (m, 2 H, CH₂CH₃), 2.03 (s, 3 H), 2.26 (s, 3 H,

SCH₃), 2.35 (td, ³J ϭ 6.6 Hz, ³J ϭ 3.0 Hz, 1 H, SCH), 2.86 (dt,

SCH(CH₃)₂], 133.0 (31), 125.0 (23), 119.0 (26), 117.0 (21), 114.0

(53), 77.1 (30) [H₂SCH(CH₃)₂^ϩ]. Ϫ HR-MS: C₃₀H₄₂⁵⁶FeN₂OS₂:

calcd. 566.208795; found 566.208816.

3

²J ϭ9.1 Hz, J ϭ 8.7 Hz, 1 H, NCH₂), 2.91 (m, 1 H, NCH), 3.14

2

3

(m, 1 H, NCH₂), 3.31 (s, 3 H, OCH₃), 3.52 (dd, J ϭ 9.1 Hz, J ϭ Hydrazine 5h: According to GP5, a solution of hydrazone 4l

5.0 Hz, 1 H, OCH₂), 3.56 (broad s, 1 H, NH), 3.56 (dd, ²J ϭ (110 mg, 0.184 mmol) in diethyl ether/CH₂Cl₂(2:1, 10.5 mL) was

9.1 Hz, ³J ϭ 5.2 Hz, 1 H, OCH₂), 3.96 (t, ³J ϭ 2.5 Hz, 1 H, treated with catecholborane (8.0 equiv.) at Ϫ40 °C. After warming

3

4

C₅H₃R₂), 4.20 (s, 5 H, C₅H₅), 4.29 (dd, J ϭ 2.5 Hz, J ϭ 1.7 Hz,

to room temperature, the reaction mixture was stirred for 48 h at

room temperature. Aqueous work up and purification by flash

3

4

1 H, C₅H₃R₂), 4.32 (dd, J ϭ 2.8 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂),

4.48 (d, ³J ϭ 2.7 Hz, 1 H, FcCH). Ϫ ¹H NMR (minor isomer, chromatography through silica gel (hexane/diethyl ether ϭ 4:1) pro-

400 MHz, C₆D₆): δ ϭ 1.28 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), vided hydrazine 5h. Ϫ Yield: 75 mg (68%, yellow oil). Ϫ R_fϭ 0.44

1.35Ϫ2.15 (m, 5 H, β-ring-CH₂, CH₂CH₃), 2.29 (s, 3 H), 2.60 (s, 3

(hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ81.7 (CHCl₃,

2

3

H, SCH₃), 2.35 (dt, J ϭ10.4 Hz, J ϭ 9.4 Hz, 1 H, NCH₂), 2.60 c ϭ 0.18). Ϫ IR (CHCl₃): ν˜ ϭ 3095 cm^Ϫ1, 3070, 3055, 2960, 2926,

(m, 1 H, CH₂CH₃), 3.25 (m, 2 H), 4.14 (m, 2 H, NCH, NCH₂, 2870, 2824, 1725, 1676, 1579, 1477, 1461, 1439, 1414, 1380, 1366,

3

OCH₂), 3.28 (s, 3 H, OCH₃), 3.52 (dt, J ϭ 11.8 Hz, J ϭ 2.7 Hz, 1287, 1242, 1218, 1198, 1155, 1124, 1108, 1069, 1035, 1023, 1001,

1

1 H, SCH), 3.99 (t, ³J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.05 (s, 5 H, C₅H₅),

970, 922, 879, 829, 757, 736, 691, 667, 535, 491, 462. Ϫ H NMR

3

4

3

4.30 (dd, J ϭ 2.8 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.31 (dd, J ϭ (300 MHz, C₆D₆): δ ϭ 1.28Ϫ1.90 (m, 5 H, β-ring-CH₂, CH₂CH₃),

2.2 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 5.34 (d, ³J ϭ 2.5 Hz, 1 H,

FcCH), 6.31 (broad s, 1 H, NH). Ϫ ¹³C NMR (major isomer,

1.32 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.35 (d, ³J ϭ 6.6 Hz, 3 H,

CHCH₃), 1.42 (d, ³J ϭ 6.6 Hz, 3 H, CHCH₃), 2.10 (dt, ²J ϭ 8.5 Hz,

100 MHz, C₆D₆): δ ϭ 13.4, 15.0, 21.2 (CH₃), 21.7, 22.7 (CH₂CH₃, ³J ϭ 8.0 Hz, 1 H, NCH₂), 2.39 (dqd, J ϭ 15.6 Hz, J ϭ 7.4 Hz,

2

3

NCH₂CH₂), 27.8 (NCHCH₂), 51.4 (SCH), 58.3, 59.2 (FcCH, ³J ϭ 3.3 Hz, 1 H, CH₂CH₃), 2.65 (qd, J ϭ 7.0 Hz, ³J ϭ 3.7 Hz, 1

3

OCH₃), 58.6 (NCH₂), 67.4, 67.7, 68.1, 72.1 (NCH, C₅H₃R₂), 70.3 H, NCH), 2.81 (broad s, 1 H, NH), 3.15 (s, 3 H, OCH₃), 3.20 [m,

(C₅H₅), 76.5 (OCH₂), 84.6, 91.4 (i-C₅H₃R₂). Ϫ ¹³C NMR (minor 3 H, OCH₂, NCH₂, SCH(CH₃)₂], 3.33 (ddd, ³J ϭ 11.0 Hz, ³J ϭ

3

2

3

isomer, 100 MHz, C₆D₆): δ ϭ 13.1, 15.6, 21.2 (CH₃), 21.1, 21.6 3.3 Hz, J ϭ 2.2 Hz, 1 H, SCHCH₂), 3.82 (dd, J ϭ 8.8 Hz, J ϭ

3

(CH₂CH₃, NCH₂CH₂), 24.2 (NCHCH₂), 51.2 (SCH), 58.8, 59.0 3.8 Hz, 1 H, OCH₂), 4.03 (t, J ϭ 2.6 Hz, 1 H, C₅H₃R₂), 4.11 (s, 5

3

4

(FcCH, OCH₃), 65.8 (NCH₂), 67.3, 71.9, 72.5, 73.8 (NCH, H, C₅H₅), 4.31 (dd, J ϭ 2.7 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.34

C₅H₃R₂), 70.5 (C₅H₅), 72.3 (OCH₂), 83.2, 94.3 (i-C₅H₃R₂). Ϫ EI-

(dd, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.48 (d, ³J ϭ 2.2 Hz,

MS; m/z: 462.0 (8) [M^ϩ], 373.0 (64) [M^ϩϪ H₃SCHCH₂CH₃], 333.0 1 H, FcCH), 6.85Ϫ6.97 (m, 3 H, m/p-C₆H₅), 7.39 (dm, ³J ϭ 6.9 Hz,

(22) [M^ϩϪ C₆H₁₃N₂O], 285.9 (100) [333.0 Ϫ H₃CS], 242.9 (24), 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 12.7 (CH₃), 20.7,

129.0 (10) [NHϪNC₆H₁₂O^ϩ].

Ϫ

HR-MS: C₂₂H₃₄⁵⁶FeN₂OS₂:

23.3 (CH₂CH₃, NCH₂CH₂), 23.6, 24.0 (CH₃), 26.9 (NCHCH₂),

35.6, 53.4 (SCH), 55.9 (NCH₂), 58.2 (OCH₃), 61.0 (FcCH), 66.1,

69.0, 70.2, 74.9 (NCH, C₅H₃R₂), 69.8 (C₅H₅), 74.6 (i-C₅H₃R₂), 75.1

(OCH₂), 94.9 (i-C₅H₃R₂), 125.5 (p-C₆H₅), 128.6, 129.2 (o/m-C₆H₅),

calcd. 462.146196; found 462.146178.

Hydrazine 5g: According to GP5, a solution of hydrazone 4k

(42 mg, 0.074 mmol) in CH₂Cl₂(3 mL) was treated with catechol-

borane (8.0 equiv.) at Ϫ60 °C. After warming to room temperature,

aqueous work up and purification by flash chromatography

through silica gel (hexane/diethyl ether ϭ 4:1) provided hydrazone

5g. Ϫ Yield: 37 mg (88%, yellow oil). Ϫ R_fϭ 0.32 (hexane/diethyl

ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ86.7 (CHCl₃, c ϭ 3.0). Ϫ

IR (CHCl₃): ν˜ ϭ 3096 cm^Ϫ1, 2961, 2925, 2870, 2826, 2732, 1724,

134.9 (i-C₆H₅). Ϫ EI-MS; m/z: 600.0 (12) [M^ϩ], 483.0 (73) [M^ϩ

Ϫ

(H₃C)₂CHSCHCH₂CH₃], 470.9 (11) [M^ϩϪ C₆H₁₃N₂O], 395.9

(47), 326.0 (51), 314.0 (100), 280.9 (13), 210.9 (23), 129.0 (19), 120.9

(11) [CpFe^ϩ]. Ϫ CI-MS (isobutane); m/z: 601.1 (100) [MH^ϩ], 70.9

(31) [M^ϩ

Ϫ

C₆H₁₃N₂O], 468.9 (18).

Ϫ

HR-MS:

C₂₉H₄₀⁵⁶FeN₂OSSe: calcd. 600.137595; found 600.137602.

1678, 1596, 1563, 1492, 1452, 1412, 1399, 1381, 1366, 1306, 1287, Hydrazine 5i: According to GP5, a solution of hydrazone 4c

1243, 1217, 1199, 1185, 1154, 1118, 1108, 1088, 1037, 1018, 1002,

(60 mg, 0.103 mmol) in diethyl ether/CH₂Cl₂(1:1, 14 mL) was

971, 923, 881, 805, 757, 667, 505, 488, 465. Ϫ ¹H NMR (300 MHz, treated with catecholborane (5.0 equiv.) at Ϫ20 °C after deprotec-

C₆D₆): δ ϭ 1.33 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.35 (d, ³J ϭ tion with TMEDA. After warming to room temperature, the reac-

3

6.7 Hz, 3 H, CHCH₃), 1.43 (d, J ϭ 6.7 Hz, 3 H, CHCH₃), 1.48 -

1.56 (m, 2 H), 1.72Ϫ1.86 (m, 3 H, β-ring-CH₂, CH₂CH₃), 1.99 (s,

tion mixture was stirred for 15 h at room temperature, cooled to 0

°C and treated with BH₃DMS (7.0 equiv.). The solution was stirred

3 H, C₆H₄CH₃), 2.13 (q, ^2/3J ϭ 8.4 Hz, 1 H, NCH₂), 2.42 (dqd, for 3 h. Aqueous work up and purification by flash chromato-

3

²J ϭ 14.8 Hz, J ϭ 7.4 Hz, J ϭ 3.4 Hz, 1 H, CH₂CH₃), 2.67 (qd,

graphy through silica gel (hexane/diethyl ether ϭ 7:1) provided hy-

³J ϭ 6.7 Hz, ³J ϭ 3.7 Hz, 1 H, NCH), 2.82 (broad s, 1 H, NH), drazone 5i. Ϫ Yield: 36 mg (58%, orange oil). Ϫ R_fϭ 0.25 (hexane/

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3419

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ112.7 (CHCl₃, c ϭ NMR (162 MHz, C₆D₆): δ ϭ ϩ23.2 (s). Ϫ EI-MS; m/z: 600.1 (3)

1.05). Ϫ IR (CHCl₃): ν˜ ϭ 3080 cm^Ϫ1, 3058, 3004, 2971, 2922, 2874, [M^ϩϪ BH₃], 471.0 (10) [600.1 Ϫ C₆H₁₃N₂O], 373.1 (26) [M^ϩ

2827, 2387, 2279, 1715, 1668, 1589, 1483, 1437, 1378, 1336, 1313, BH₃Ϫ Ph₂PCHCH₂CH₃], 286.0 (100) [471.0 Ϫ Ph₂P], 243.0 (14).

Ϫ

1279, 1217, 1189, 1107, 1063, 1029, 1001, 969, 921, 896, 876, 822,

Ϫ CI-MS (isobutane); m/z: 601.1 (100) [MH^ϩ], 600.0 (84) [M^ϩ].

1

756, 698, 667, 611, 581, 498, 483. Ϫ H NMR (400 MHz, C₆D₆): Ϫ HR-MS: C₃₃H₄₁⁵⁶FeN₂OPS (M^ϩϪ BH₃): calcd. 600.202662;

3

δ ϭ 1.23Ϫ2.12 (m, 5 H, β-ring-CH₂, NCH₂), 1.60 (dd, J_HP

ϭ

found 600.202770.

15.9 Hz, ³J ϭ 7.4 Hz, 3 H, CHCH₃), 2.03 (s, 3 H, SCH₃), 2.67

Bis(hydrazine) 12: According to GP5, a solution of hydrazone 11

(700 mg, 1.14 mmol) in CH₂Cl₂(25 mL) was treated with catechol-

borane (8.0 equiv.) at Ϫ50 °C. After warming to room temperature,

the reaction mixture was stirred for 24 h at room temperature.

Aqueous workup and purification by flash chromatography

through silica gel (hexane/diethyl ether ϭ 4:1) provided hydrazone

12. Ϫ Yield: 263 mg (37%, red-orange oil). Ϫ R_fϭ 0.15 (hexane/

(ddd, ²J ϭ 9.1 Hz, ³J ϭ 7.1 Hz, ³J ϭ 4.4 Hz, 1 H, NCH₂), 2.84 (m,

2

3

1 H, NH), 3.02 (dd, J ϭ 8.5 Hz, J ϭ 7.7 Hz, 1 H, OCH₂), 3.10

2

3

(s, 3 H, OCH₃), 3.18 (m, 1 H, NCH), 3.41 (dd, J ϭ 9.1 Hz, J ϭ

3.3 Hz, 1 H, OCH₂), 3.79 (dqd, ²J_HPϭ 15.1 Hz, ³J ϭ 7.4 Hz, ³J ϭ

3

1.7 Hz, 1 H, PCH), 3.89 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.07 (s, 5

H, C₅H₅), 4.16 (m, 1 H, C₅H₃R₂), 4.23 (dd, ³J ϭ 2.2 Hz, ⁴J ϭ

3

1.4 Hz, 1 H, C₅H₃R₂), 4.67 (dd, J_HPϭ 9.6 Hz, J ϭ 1.7 Hz, 1 H,

FcCH), 7.01Ϫ7.24 (m, 6 H, m/p-C₆H₅), 8.06 (m, 2 H, o-C₆H₅), 8.32

(m, 2 H, o-C₆H₅). Ϫ ¹³C NMR (100 MHz, C₆D₆): δ ϭ 10.0 (SCH₃),

20.6 (NCH₂CH₂), 21.9 (PCHCH₃), 26.9 (NCHCH₂), 38.4 (d,

¹J_CPϭ 30.3 Hz, PCH), 54.8 (FcCH), 57.3 (NCH₂), 58.7 (OCH₃),

65.7, 67.7, 70.9, 71.9 (NCH, C₅H₃R₂), 70.4 (C₅H₅), 75.1 (OCH₂),

83.0 (i-C₅H₃R₂), 128.8 (d, ³J_CPϭ 9.2 Hz), 128.9 (d, ³J_CPϭ 9.1 Hz,

diethyl ether ϭ 4:1). Ϫ dr ϭ 1:1:1. Ϫ IR (neat): ν˜ ϭ 3089 cm^Ϫ1

,

2967, 2920, 2873, 2827, 2379, 2279, 1725, 1666, 1600, 1447, 1373,

1308, 1237, 1197, 1188, 1126, 1039, 1025, 946, 918, 879, 827, 710,

675, 604, 531, 501, 489. Ϫ ¹H NMR (300 MHz, C₆D₆, selected

signals): δ ϭ 1.73 (s, 3 H, SCH₃), 3.32 (s, 3 H, OCH₃), 4.63 (broad

s, 1 H, FcCH). Ϫ EI-MS; m/z: 618.3 (21) [M^ϩ], 413.1 (59) M^ϩ

Ϫ

H₃CSCHCH₃Ϫ C₆H₁₄N₂O), 366.1 (33, 413.1 Ϫ SCH₃), 359.0 (62),

337.0 (71, 413.1 Ϫ H₃CCH₂SCH₃), 313.0 (55), 289.1 (40), 265.9

(49), 129.1 (100, HNNC₆H₁₂O^ϩ). Ϫ HR-MS: C₃₀H₅₀⁵⁶FeN₄O₂S₂:

calcd. 618.272458; found 618.271830.

1

m-C₆H₅), 129.6 (d, J_CPϭ 52.1 Hz), 130.4 (d, J_CPϭ 58.4 Hz, i-

4

2

C₆H₅), 131.0, 131.2 (d, J_CPϭ 2.3 Hz, p-C₆H₅), 133.3 (d, J_CP

ϭ

8.6 Hz), 134.0 (d, ²J_CPϭ 8.1 Hz, o-C₆H₅). Ϫ ³¹P NMR (162 MHz,

C₆D₆): δ ϭ ϩ23.9 (broad). Ϫ EI-MS; m/z: 600.3 (11) [M^ϩ], 471.2

(38) [M^ϩϪ C₆H₁₃N₂O], 469.2 (51) [471.2 Ϫ H₂], 424.3 (21) [471.2

Ϫ SCH₃], 272.1 (100) [471.2 Ϫ Ph₂PBH₃], 185.2 (26) [PPh₂^ϩ], 129.2

(18) [C₁₀H₉^ϩ], 121.0 (13) [CpFe^ϩ], 57.3 (15) [FeH^ϩ]. Ϫ HR-MS:

C₃₂H₄₂B⁵⁶FeN₂OPS: calcd. 600.219792; found 600.219805.

General Procedure for the Preparation of PʜS Ligands 6 (GP6):

HBF₄·OEt₂(2.5 equiv.) was added to a solution of hydrazine 5 in

CH₂Cl₂(25Ϫ60 mL mmol^Ϫ1) at 0 °C. After 30 s (E¹ϭ R₂PBH₃)

or 1 h (E¹ϭ SR), a solution of HBEt₃Li (1  in THF, 5 equiv.) was

added. The dark brown solution immediately underwent a colour

change to yellow. After 10 min, the reaction was quenched with

saturated aqueous NH₄Cl, washed with brine and dried with

MgSO₄. The pure product was obtained by filtration through silica

gel (hexane/ether ϭ 4:1).

Hydrazine 5j: According to GP5, a solution of hydrazone 4b

(157 mg, 0.262 mmol) in diethyl ether/CH₂Cl₂(1:1, 26 mL) was

treated with catecholborane (5.0 equiv.) at Ϫ20 °C after deprotec-

tion with TMEDA. After warming to room temperature, the reac-

tion mixture was stirred for 15 h at room temperature, cooled to 0

°C and treated with BH₃DMS (7.0 equiv.). The solution was stirred

for 3 h. Aqueous work up and purification by flash chromato-

graphy through silica gel (hexane/diethyl ether ϭ 7:1) provided hy-

drazone 5j. Ϫ Yield: 65 mg (40%, yellow oil). Ϫ R_fϭ 0.20 (hexane/

diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ94.6 (CHCl₃, c ϭ

1.23). Ϫ IR (CHCl₃): ν˜ ϭ 3080 cm^Ϫ1, 3058, 3005, 2968, 2923, 2875,

2827, 2388, 2271, 1723, 1665, 1589, 1483, 1461, 1437, 1384, 1337,

1313, 1259, 1217, 1188, 1107, 1065, 1029, 1001, 970, 918, 876, 822,

756, 699, 667, 611, 581, 540, 498, 482. Ϫ ¹H NMR (400 MHz,

General Procedure for the Preparation of SʜS- and SʜSe Ligands 6

(GP7): To trifluoroacetic acid (SʜS ligands: 10 mL mmol^Ϫ1; SʜSe

ligands: 10 equiv.) was added NaBH₄(SʜS ligands: 0.5 g mmol^Ϫ1

;

SʜSe ligands: 5 equiv.) at 0 °C. Subsequently, the solution of hy-

drazine 5 in CH₂Cl₂(20 mL mmol^Ϫ1) was injected and the mixture

was allowed to reach room temperature slowly. After completion

of the reaction, it was quenched with saturated aqueous NH₄Cl,

washed twice with saturated aqueous K₂CO₃and twice with brine,

and dried with MgSO₄. The pure product was obtained by filtra-

tion through silica gel (hexane/ether ϭ 10:1).

3

C₆D₆): δ ϭ 0.89 (t, J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.25Ϫ1.53 (m, 3

2

H), 1.73 (m, 1 H, β-ring-CH₂), 2.00 (s, 3 H, SCH₃), 2.11 (dt, J ϭ

General Procedure for BH₃Deprotection (GP8): A heated Schlenk

flask was charged under argon with a solution of BH₃-protected

phosphane 6a؊f in dry diethyl ether, THF or toluene (2 mL

mmol^Ϫ1) depending on the solubility. Then TMEDA (2.5Ϫ5.0

equiv.) was added at room temperature. If the deprotection required

higher temperatures (alkyl-substituted phosphanes), the reaction

was run in toluene at 90 °C. After completion (TLC control) the

solvent was removed in vacuo. The ligand was obtained after filtra-

tion through silica gel.

8.8 Hz, ³J ϭ 8.0 Hz, 1 H, NCH₂), 2.24 (m, 2 H, CH₂CH₃), 2.69

(ddd, ²J ϭ 9.1 Hz, ³J ϭ 7.4 Hz, ³J ϭ 4.4 Hz, 1 H, NCH₂), 2.81

3

2

(qd, J ϭ 7.3 Hz, J ϭ 3.6 Hz, 1 H, NCH), 3.06 (dd, J ϭ 8.8 Hz,

³J ϭ 7.4 Hz, 1 H, OCH₂), 3.15 (s, 3 H, OCH₃), 3.47 (dd, ²J ϭ

8.8 Hz, ³J ϭ 3.6 Hz, 1 H, OCH₂), 3.72 (dddd, J_HPϭ 14.0 Hz,

2

³J ϭ 10.7 Hz, J ϭ 3.0 Hz, J ϭ 1.7 Hz, 1 H, PCH), 3.92 (t, J ϭ

2.6 Hz, 1 H, C₅H₃R₂), 4.20 (s, 5 H, C₅H₅), 4.20 (m, 1 H, C₅H₃R₂),

4.22 (dd, ³J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.66 (dd, ²J_HPϭ

11.5 Hz, ³J ϭ 1.1 Hz, 1 H, FcCH), 7.01Ϫ7.21 (m, 6 H, m/p-C₆H₅),

3

8.12 (m, 2 H, o-C₆H₅), 8.31 (m, 2 H, o-C₆H₅). Ϫ ¹³C NMR BH₃-Protected PʜS Ligand 6a: According to GP6, a solution of

3

(75 MHz, C₆D₆): δ ϭ 15.1 (d, J_CPϭ 3.8 Hz, CH₂CH₃), 19.4 (d, hydrazine 5i (80 mg, 0.133 mmol) in CH₂Cl₂(10 mL) was treated

²J_CPϭ 4.3 Hz, CH₂CH₃), 20.4 (SCH₃), 21.8 (NCH₂CH₂), 27.0

with HBF₄OEt₂(2.5 equiv.) at 0 °C. After 30 s, a solution of

(NCHCH₂), 44.7 (d, ¹J_CPϭ 28.0 Hz, PCH), 55.9 (d, ²J_CPϭ 2.8 Hz, HBEt₃Li (5.0 equiv., 1  in THF) was added. The reaction mixture

FcCH), 57.2 (NCH₂), 58.8 (OCH₃), 65.5 (NCH), 67.8, 69.2 71.4 was stirred for 10 min and worked up. Filtration through silica gel

(C₅H₃R₂), 70.4 (C₅H₅), 75.0 (OCH₂), 84.1, 97.2 (d, J_CPϭ 12.6 Hz,

i-C₅H₃R₂), 128.7 (d, J_CPϭ 6.3 Hz), 128.9 (d, J_CPϭ 6.3 Hz, m-

(hexane/diethyl ether ϭ 4:1) provided BH₃-protected phosphane 6a.

Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ de ϭ 94%. Ϫ ee Ն 99% (HPLC: Chiralcel OD-H,

3

1

C₆H₅), 130.2 (d, J_CPϭ 52.1 Hz), 131.8 (d, J_CPϭ 51.5 Hz, i-

4

C₆H₅), 130.9 (d, J_CPϭ 2.3 Hz), 131.0 (d, J_CPϭ 2.3 Hz, p-C₆H₅),

cHex, 0.5 mL/min, ent-1: 66.87 min; ent-2: 44.27 min). Ϫ [α]²_D⁵

ϭ

133.5 (d, J_CPϭ 8.6 Hz), 134.1 (d, J_CPϭ 8.0 Hz, o-C₆H₅). Ϫ ³¹P ϩ15.6 (CHCl₃, c ϭ 0.27). Ϫ IR (CHCl₃): ν˜ ϭ 3079 cm^Ϫ1, 3058,

2

3420 Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

3006, 2971, 2921, 2873, 2855, 2385, 2350, 2263, 1723, 1659, 1589, (hexane/diethyl ether ϭ 10:1) provided BH₃-protected phosphane

FULL PAPER

1482, 1437, 1379, 1313, 1218, 1186, 1161, 1137, 1107, 1064, 822,

757, 696, 668, 588, 495, 453. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ

6c. Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ Yield: 27 mg (95%, yellow crystals). Ϫ R_fϭ 0.53

1

3

1.20 (dd, J_HPϭ 16.2 Hz, J ϭ 7.1 Hz, 3 H, CH₂CH₃), 1.97 (s, 3 (hexane/diethyl ether ϭ 4:1). Ϫ de ϭ 95%. Ϫ ee Ն 96% (¹H NMR:

2

3

H, SCH₃), 2.66 (dqt, J_HPϭ 14.2 Hz, J ϭ 7.1 Hz, J ϭ 1.9 Hz, 1 22.5 equiv. Pirkle alcohol in C₆D₆, C₅H₅: 4.020 v 4.024; SCH₃:

H, PCH), 3.05 (m, 2 H, FcCH₂), 3.81 (t, ³J ϭ 2.5 Hz, 1 H, 1.552 v 1.560; CHCH₃: 1.181 v 1.197 ppm). Ϫ [α]²_D⁵ϭ Ϫ149.4

(CHCl₃, c ϭ 0.33). Ϫ M.p.: 151 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3078 cm^Ϫ1

3

4

C₅H₃R₂), 3.84 (s, 5 H, C₅H₅), 3.92 (dd, J ϭ 2.5 Hz, J ϭ 1.4 Hz,

,

3

4

1 H, C₅H₃R₂), 4.10 (dd, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 3057, 3006, 2962, 2920, 2858, 2396, 2352, 2263, 1818, 1777, 1728,

7.02 (m, 6 H, m/p-C₆H₅), 7.79 (m, 2 H, o-C₆H₅), 7.88 (m, 2 H, o- 1665, 1589, 1484, 1437, 1396, 1374, 1334, 1314, 1267, 1235, 1218,

C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ14.6 (d, J_CPϭ 2.3 Hz, 1179, 1152, 1106, 1062, 1043, 1029, 1002, 956, 926, 893, 825, 743,

2

CHCH₃), 19.9 (SCH₃), 30.0 (d, J_CPϭ 4.6 Hz, FcCH₂), 31.7 (d, 699, 667, 654, 636. Ϫ ¹H NMR (300 MHz, C₆D₆): δ ϭ 1.24 (d,

2

¹J_CPϭ 13.8 Hz, PCH), 67.2, 68.7, 70.9 (C₅H₃R₂), 70.4 (C₅H₅), ³J ϭ 6.3 Hz, 3 H, CHCH₃), 1.60 (s, 3 H, SCH₃), 2.31 (dd, ²J ϭ

84.8, 88.8 (d, J_CPϭ 13.8 Hz, i-C₅H₃R₂), 128.8 (d, J_CPϭ 9.8 Hz), 13.8 Hz, ³J ϭ 11.5 Hz, 1 H, FcCH₂), 2.43 (dqd, ³J ϭ 11.4 Hz, ³J ϭ

3

128.9 (d, ³J_CPϭ 9.2 Hz, m-C₆H₅), 129.6 (d, ¹J_CPϭ 52.1 Hz), 129.8

6.3 Hz, ³J ϭ 3.3 Hz, 1 H, SCH), 3.68 (dd, ²J ϭ 14.3 Hz, ³J ϭ

1

4

3

(d, J_CPϭ 52.1 Hz, i-C₆H₅), 131.0 (d, J_CPϭ 2.3 Hz), 131.1 (d, 3.3 Hz, 1 H, FcCH₂), 3.71 (m, 1 H, C₅H₃R₂), 4.01 (t, J ϭ 2.5 Hz,

⁴J_CPϭ 2.8 Hz, p-C₆H₅), 133.02 (d, J_CPϭ 8.6 Hz), 133.03 (d,

1 H, C₅H₃R₂), 4.05 (s, 5 H, C₅H₅), 4.39 (dt, ³J ϭ 2.2 Hz, ⁴J ϭ

J_HPϭ 1.8 Hz, 1 H, C₅H₃R₂), 6.94Ϫ7.03 (m, 6 H, m/p-C₆H₅), 7.66

2

²J_CPϭ 8.0 Hz, o-C₆H₅). Ϫ ³¹P NMR (C₆D₆, 121 MHz): ϩ24.4

(broad). Ϫ EI-MS; m/z: 472.2 (14) [M^ϩ], 458.1 (49) [M^ϩϪ BH₃], (m, 2 H, o-C₆H₅), 7.78 (m, 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz,

443.1 (100) [458.1 Ϫ CH₃], 411.1 (15) [458.1 Ϫ SCH₃], 393.1 (13) C₆D₆): δ ϭ12.9, 22.0 (CH₃), 36.9 (FcCH₂), 43.9 (SCH), 70.2 (d,

[458.1 Ϫ C₅H₅], 226.1 (10) [Ph₂P(BH₃)CHϭCH₂^ϩ]. Ϫ HR-MS:

J_CPϭ 6.1 Hz), 73.3 (d, J_CPϭ 3.7 Hz), 76.1 (d, J_CPϭ 8.0 Hz,

C₅H₃R₂), 70.8 (C₅H₅), 71.5, 91.7 (d, J_CPϭ 16.5 Hz, i-C₅H₃R₂),

C₂₆H₃₀B⁵⁶FePS: calcd. 472.124829; found 472.124732.

3

4

128.5 (d, J_CPϭ 9.7 Hz, m-C₆H₄), 130.7 (d, J_CPϭ 2.5 Hz, p-

C₆H₄), 130.9 (d, ⁴J_CPϭ 2.4 Hz, p-C₆H₄), 131.9 (d, ¹J_CPϭ 59.9 Hz,

i-C₆H₄), 132.95 (d, J_CPϭ 56.2 Hz, i-C₆H₄), 132.95 (d, J_CP

BH₃-Protected PʜS Ligand 6b: According to GP6, a solution of

hydrazine 5j (127 mg, 0.207 mmol) in CH₂Cl₂(5 mL) was treated

with HBF₄OEt₂(2.5 equiv.) at 0 °C. After 30 s, a solution of

HBEt₃Li (5.0 equiv., 1  in THF) was added. The reaction mixture

was stirred for 10 min and worked up. Filtration through silica gel

(hexane/diethyl ether ϭ 10:1) provided BH₃-protected phosphane

6b. Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ Yield: 51 mg (51%, yellow oil). Ϫ R_fϭ 0.48 (hex-

ane/diethyl ether ϭ 4:1). Ϫ de ϭ 97%. Ϫ ee Ն 99% (HPLC:

Chiralcel OD-H, cHex, 0.5 mL/min, ent-1: 43.44 min; ent-2:

30.85 min). Ϫ [α]²_D⁵ϭ Ϫ22.4 (CHCl₃, c ϭ 0.92). Ϫ IR (CHCl₃):

ν˜ ϭ 3080 cm^Ϫ1, 3059, 3007, 2961, 2923, 2874, 2852, 2386, 2268,

1723, 1667, 1483, 1461, 1437, 1381, 1314, 1217, 1185, 1160, 1139,

1106, 1063, 1030, 1001, 964, 822, 756, 696, 668, 590, 499. Ϫ ¹H

NMR (400 MHz, C₆D₆): δ ϭ 0.85 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃),

1.77 (m, 2 H, CH₂CH₃), 2.03 (s, 3 H, SCH₃), 2.61 (m, 1 H, PCH),

1

2

ϭ

9.2 Hz, o-C₆H₄), 133.8 (d, J_CPϭ 9.1 Hz, o-C₆H₅). Ϫ ³¹P NMR

(C₆D₆, 162 MHz): ϩ14.6 (broad). Ϫ EI-MS; m/z: 472.1 (2) [M^ϩ],

458.0 (37) [M^ϩϪ BH₃], 443.0 (100) [458.0 Ϫ CH₃], 376.9 (12),

225.9 (94) [FcCHϭCHCH₃^ϩ], 182.9 (35) [PPh₂^ϩϪ H₂], 132.9 (10),

120.9 (12) [CpFe^ϩ], 56.0 (11) [Fe^ϩ] Ϫ CI-MS (isobutane); m/z:

472.0 (44) [M^ϩ], 471.1 (100) [M^ϩϪ H], 458.0 (6) [M^ϩϪ BH₃]. Ϫ

HR-MS: C₂₆H₂₇⁵⁶FePS (M^ϩϪ BH₃): calcd. 458.092049; found

458.092016.

2

BH₃-Protected PʜS Ligand 6d: According to GP6, a solution of

hydrazine 5c (112 mg, 0.182 mmol) in CH₂Cl₂(4 mL) was treated

with HBF₄· OEt₂(2.5 equiv.) at 0 °C. After 45 min, a solution of

HBEt₃Li (5.0 equiv., 1  in THF) was added. The reaction mixture

was stirred for 10 min and worked up. Filtration through silica gel

(hexane/diethyl ether ϭ 10:1) provided BH₃-protected phosphane

6d. Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ Yield: 80 mg (90%, yellow crystals). Ϫ R_fϭ 0.52

(hexane/diethyl ether ϭ 4:1). Ϫ de ϭ 97%. Ϫ ee Ն 96% (¹H NMR:

22 equiv. Pirkle alcohol in C₆D₆, C₅H₅: 4.058 v 4.065 ppm). Ϫ

[α]_D²⁵ϭ Ϫ192.4 (CHCl₃, c ϭ 0.21). Ϫ M.p.: 142 °C. Ϫ IR (CHCl₃):

ν˜ ϭ 3077 cm^Ϫ1, 3057, 3006, 2962, 2924, 2872, 2855, 2392, 2351,

2262, 1667, 1484, 1460, 1437, 1383, 1336, 1313, 1295, 1261, 1218,

1179, 1149, 1197, 1062, 1043, 1029, 1001, 954, 924, 824, 757, 699,

2

3

3.07 (ddd, J ϭ 14.8 Hz, J ϭ 9.3 Hz, J ϭ 6.1 Hz, 1 H, FcCH₂),

3.26 (dt, ²J ϭ 15.1 Hz, ³J ϭ 7.9 Hz, 1 H, FcCH₂), 3.64 (t, ³J ϭ

3

2.5 Hz, 1 H, C₅H₃R₂), 3.84 (s, 5 H, C₅H₅), 3.92 (dd, J ϭ 2.4 Hz,

⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 4.01 (dd, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1

H, C₅H₃R₂), 6.98 (m, 6 H, m/p-C₆H₅), 7.86 (m, 4 H, o-C₆H₅). Ϫ

¹³C NMR (100 MHz, C₆D₆): δ ϭ13.9 (d, ³J_CPϭ 8.6 Hz, CH₂CH₃),

3

4

2

19.6 (SCH₃), 24.0 (d, J_CPϭ 2.8 Hz, CH₂CH₃), 29.1 (d, J_CP

4.6 Hz, FcCH₂), 38.1 (d, J_CPϭ 33.2 Hz, PCH), 66.8, 69.5, 70.3

(C₅H₃R₂), 70.4 (C₅H₅), 84.6, 88.7 (i-C₅H₃R₂), 128.6 (d, J_CP

ϭ

1

3

ϭ

3

9.7 Hz, m-C₆H₅), 128.9 (d, J_CPϭ 9.8 Hz, m-C₆H₅), 130.8 (d,

1

⁴J_CPϭ 2.3 Hz, p-C₆H₅), 131.0 (d, J_CPϭ 2.3 Hz, p-C₆H₅), 132.9

4

667, 655, 624, 604, 539, 503, 480. Ϫ H NMR (300 MHz, C₆D₆):

3

2

δ ϭ 0.95 (t, J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.55 (m, 2 H, CH₂CH₃),

(d, J_CPϭ 8.6 Hz, o-C₆H₅) 133.0 (d, J_CPϭ 8.6 Hz, o-C₆H₅). Ϫ

³¹P NMR (C₆D₆, 121 MHz): ϩ23.0 (broad). Ϫ EI-MS; m/z: 486.4

(4) [M^ϩ], 472.3 (41) [M^ϩϪ BH₃], 457.2 (100) [472.3 Ϫ CH₃], 425.2

(38) [472.3 Ϫ SCH₃], 407.1 (13), 304.2 (45) [425.2 Ϫ CpFe], 286.1

(27) [M^ϩϪ Ph₂PBH₃], 240.1 (37) [Ph₂P(BH₃)CHϭCHCH₃^ϩ],

185.1 (21) [Ph₂P^ϩ], 183.1 (63) [185.1 Ϫ H₂], 121.0 (84) [CpFe^ϩ],

109.1 (38), 91.2 (45), 57.3 (36), 56.2 (38) [Fe^ϩ], 55.2 (35). Ϫ HR-

2

1.58 (s, 3 H, SCH₃), 2.18 (m, 1 H, SCH), 2.38 (dd, J ϭ 14.3 Hz,

2

3

³J ϭ 11.3 Hz, 1 H, FcCH₂), 3.67 (dd, J ϭ 14.5 Hz, J ϭ 4.1 Hz,

1 H, FcCH₂), 3.70 (m, 1 H, C₅H₃R₂), 4.02 (t, ³J ϭ 2.5 Hz, 1 H,

C₅H₃R₂), 4.09 (s, 5 H, C₅H₅), 4.45 (dt, J ϭ 2.2 Hz, J ϭ J_HP

3

4

ϭ

1.7 Hz, C₅H₃R₂), 6.94Ϫ7.02 (m, 6 H, m/p-C₆H₅), 7.67 (m, 2 H, o-

C₆H₅), 7.80 (m, 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ

11.0, 12.4 (CH₃), 27.7 (CH₂CH₃), 34.5 (FcCH₂), 50.5 (SCH), 70.1

MS: C₂₇H₂₉⁵⁶FePS (M^ϩ

472.107697.

Ϫ BH₃): calcd. 472.107695; found

(d, J_CPϭ 6.3 Hz), 73.3, 76.0 (d, J_CPϭ 7.4 Hz, C₅H₃R₂), 70.8

1

(C₅H₅), 91.8 (i-C₅H₃R₂), 130.8, 130.9 (p-C₆H₅), 131.7 (d, J_CP

ϭ

1

2

BH₃-Protected PʜS Ligand 6c: According to GP6, a solution of

hydrazine 5b (36 mg, 0.060 mmol) in CH₂Cl₂(3 mL) was treated

with HBF₄· OEt₂(2.5 equiv.) at 0 °C. After 45 min, a solution of

HBEt₃Li (5.0 equiv., 1  in THF) was added. The reaction mixture

was stirred for 10 min and worked up. Filtration through silica gel

59.5 Hz), 133.8 (d, J_CPϭ 69.8 Hz, i-C₆H₅), 133.1 (d, J_CP

ϭ

9.1 Hz), 133.8 (d, J_CPϭ 9.1 Hz, o-C₆H₅). Ϫ ³¹P NMR (C₆D₆,

121 MHz): ϩ14.0 (broad). Ϫ EI-MS; m/z: 472.1 (60) [M^ϩϪ BH₃],

458.1 (37) [M^ϩϪ CH₂ϭCH₂], 457.1 (100) [M^ϩϪ CH₂CH₃], 240.0

2

(54) [FcCHϭCHCH₂CH₃^ϩ], 183.1 (38) [PPh₂Ϫ H₂], 121.0 (68)

ϩ

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3421

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

[CpFe^ϩ], 56.1 (12) [Fe^ϩ]. Ϫ HR-MS: C₂₇H₂₉⁵⁶FePS (M^ϩϪ BH₃):

calcd. 472.107699; found 472.107688.

5 H, C₅H₅), 4.52 (q, ^3/4J ϭ J_HPϭ 2.0 Hz, 1 H, C₅H₃R₂), 7.00 (m,

6 H, m/p-C₆H₅), 7.67 (m, 2 H, o-C₆H₅), 7.79 (ddd, J ϭ 10.7 Hz,

J ϭ 8.3 Hz, J ϭ 2.7 Hz, 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz,

C₆D₆): δ ϭ 23.3, 23.9, 24.0 (CH₃), 33.2, 41.4 (SCH), 37.5 (FcCH₂),

BH₃-Protected PʜS Ligand 6e: According to GP6, a solution of

hydrazine 5d (45 mg, 0.082 mmol) in CH₂Cl₂(5 mL) was treated

with HBF₄· OEt₂(2.5 equiv.) at 0 °C. After 2 h, a solution of

HBEt₃Li (5.0 equiv., 1  in THF) was added. The reaction mixture

was stirred for 10 min and worked up. Filtration through silica gel

(hexane/diethyl ether ϭ 10:1) provided BH₃-protected phosphane

6e. Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ Yield: 30 mg (88%, yellow crystals). Ϫ R_fϭ 0.68

(hexane/diethyl ether ϭ 4:1). Ϫ de ϭ 95%. Ϫ ee Ն 96% (¹H NMR:

15 equiv. Pirkle alcohol in C₆D₆, C₅H₅: 4.081 v 4.086 ppm). Ϫ

[α]_D²⁵ϭ ϩ100.0 (CHCl₃, c ϭ 0.08). Ϫ M.p.: 73 °C. IR (CHCl₃): ν˜ ϭ

3096 cm^Ϫ1, 2923, 2854, 2727, 2384, 2350, 2263, 1739, 1659, 1643,

1579, 1462, 1379, 1293, 1261, 1154, 1108, 1068, 1044, 1033, 956,

2

68.0 (d, J_CPϭ 6.2 Hz, i-C₅H₃R₂), 70.4 (d, J_CPϭ 6.3 Hz), 70.6 (d,

1

J_CPϭ 7.5 Hz), 76.2 (C₅H₃R₂), 70.8 (C₅H₅), 91.6 (d, J_CP

ϭ

16.1 Hz, i-C₅H₃R₂), 128.5 (d, ³J_CPϭ 8.0 Hz, m-C₆H₄), 130.7, 130.9

1

(p-C₆H₄), 132.0 (d, J_CPϭ 60.1 Hz), 133.03 (d, J_CPϭ 56.1 Hz, i-

C₆H₄), 132.96 (d, ²J_CPϭ 9.1 Hz), 133.8 (d, ²J_CPϭ 9.1 Hz, o-C₆H₅).

Ϫ

³¹P NMR (C₆D₆, 162 MHz): ϩ14.1 (broad). Ϫ EI-MS; m/z:

500.4 (2) [M^ϩ], 486.3 (7) [M^ϩϪ BH₃], 443.2 (68) [486.1 Ϫ

CH(CH₃)₂], 279.3 (26), 226.1 (44) [FcCHϭCHCH₃^ϩ], 182.9 (23)

[PPh₂Ϫ H₂], 167.0 (58), 139.1 (16), 121.0 (23) [CpFe^ϩ], 113.2

ϩ

(23), 112.2 (15), 111.2 (17), 77.1 (46) [C₆H₅^ϩ], 73.2 (42), 57.2 (100)

[FeH^ϩ], 55.1 (73), 45.3 (37). Ϫ HR-MS: C₂₈H₃₄B⁵⁶FePS: calcd.

500.156129; found 500.156166.

932, 885, 822, 752, 722, 687, 652, 633, 586, 528, 483, 465. Ϫ ¹H

3

NMR (400 MHz, C₆D₆): δ ϭ 0.92 (dd, J_HPϭ 13.8 Hz, ³J ϭ SʜS Ligand 6g: According to GP7, a mixture of TFA (1 mL) and

3

7.1 Hz, 3 H, PCHCH₃), 1.10 (dd, J_HPϭ 14.8 Hz, J ϭ 7.4 Hz, 3

NaBH₄(13.3 equiv.) in CH₂Cl₂(4 mL) was treated with a solution

H, PCHCH₃), 1.12 (t, ³J ϭ 7.2 Hz, 3 H, CH₂CH₃), 1.12 (dd, of hydrazine 5f (65 mg, 0.140 mmol) in CH₂Cl₂(2 mL). After

3

³J_HPϭ 14.3 Hz, ³J ϭ 7.4 Hz, 3 H, PCHCH₃), 1.21 (dd, J_HP

ϭ

warming to room temperature, the mixture was stirred for 8 h.

14.3 Hz, J ϭ 7.2 Hz, 3 H, PCHCH₃), 1.62 (dquint, J ϭ 14.0 Hz, Aqueous work up and purification by filtration through silica gel

3

2

³J ϭ 7.2 Hz, 1 H, CH₂CH₃), 1.70 (tqd, ²J ϭ 14.3 Hz, ³J ϭ 7.1 Hz,

(hexane/diethyl ether ϭ 4:1) provided SʜS ligand 6g. Ϫ Yield:

³J ϭ 4.7 Hz, 1 H, CH₂CH₃), 1.79 (s, 3 H, SCH₃), 1.93 (dsept, 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl ether ϭ 4:1).

2

²J_HPϭ 11.0 Hz, ³J ϭ 7.1 Hz, 1 H, PCH), 1.99 (dsept, J_HP

ϭ

Ϫ Yield: 45 mg (95%, yellow crystals). Ϫ R_fϭ 0.80 (hexane/diethyl

11.0 Hz, ³J ϭ 7.2 Hz, 1 H, PCH), 2.64 (ddt, ³J ϭ 8.5 Hz, ³J ϭ ether ϭ 4:1). Ϫ de ϭ 94%. Ϫ ee Ն 99% (GC: Chirasil dex 25m,

7.7 Hz, ³J ϭ 5.5 Hz, 1 H, SCH), 2.82 (dd, ²J ϭ 15.1 Hz, ³J ϭ 140-1-190, ent-1: 56.8 min; ent-2: 57.2 min). Ϫ [α]²_D⁵ϭ Ϫ181.3

8.5 Hz, 1 H, FcCH₂), 3.20 (dd, ²J ϭ 15.4 Hz, ³J ϭ 5.2 Hz, 1 H,

FcCH₂), 3.99 (dt, ³J ϭ 2.5 Hz, ⁴J ϭ 1.7 Hz, 1 H, C₅H₃R₂), 4.04 (t,

(CHCl₃, c ϭ 0.79). Ϫ Mp: 165 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3093 cm^Ϫ1

2963, 2918, 2872, 2856, 1630, 1593, 1435, 1379, 1311, 1262, 1239,

,

³J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.13 (s, 5 H, C₅H₅), 4.49 (dt, ³J ϭ 1182, 1159, 1106, 1071, 1031, 1001, 957, 921, 875, 818, 757, 714,

4

1

2.5 Hz, J ϭ J_HPϭ 1.4 Hz, 1 H, C₅H₃R₂). Ϫ ¹³C NMR (75 MHz,

667, 515, 498, 467, 452. Ϫ H NMR (300 MHz, C₆D₆): δ ϭ 1.08

3

C₆D₆): δ ϭ11.7, 13.0 (SCH₃, CH₂CH₃), 17.0, 18.0, 18.6 (CHCH₃), (t, J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.58 (m, 2 H, CH₂CH₃), 1.76 (s, 3

1

23.7 (d, J_CPϭ 34.4 Hz), 25.3 (d, J_CPϭ 33.2 Hz, PCH), 28.4 H), 2.00 (s, 3 H, SCH₃), 2.48 (m, 1 H, SCH), 2.60 (dd, ²J ϭ

3

2

3

(CH₂CH₃), 30.2 (FcCH₂), 50.0 (SCH), 65.9 (i-C₅H₃R₂), 69.5, 71.9,

14.0 Hz, J ϭ 8.2 Hz, 1 H, FcCH₂), 3.13 (dd, J ϭ 14.0 Hz, J ϭ

73.3 (C₅H₃R₂), 71.1 (C₅H₅), 90.3 (i-C₅H₃R₂). Ϫ ³¹P NMR (C₆D₆, 5.7 Hz, 1 H, FcCH₂), 3.93 (t, J ϭ 2.6 Hz, 1 H, C₅H₃R₂), 3.99 (s,

121 MHz): ϩ31.8 (broad). Ϫ EI-MS; m/z: 418.2 (12) [M^ϩ], 404.3 5 H, C₅H₅), 4.18 (dd, ³J ϭ 2.5 Hz, ⁴J ϭ 1.7 Hz, 1 H, C₅H₃R₂),

(12) [M^ϩϪ BH₃], 389.2 (100) [404.3 Ϫ CH₃] 357.2 (10) [404.3 Ϫ 4.24 (dd, ³J ϭ 2.5 Hz, ⁴J ϭ 1.7 Hz, 1 H, C₅H₃R₂). Ϫ ¹³C NMR

3

SCH₃], 271.1 (12) [389.2 Ϫ HP(iPr)₂], 240.1 (36) [357.2 Ϫ P(iPr)₂],

(75 MHz, C₆D₆): δ ϭ 11.7, 13.4, 20.4 (CH₃), 27.7 (CH₂CH₃), 34.5

171.3 (13), 135.1 (11), 121.1 (25) [CpFe^ϩ], 57.3 (40) [FeH^ϩ], 56.3 (FcCH₂), 51.2 (SCH), 67.5, 70.4, 71.7 (C₅H₃R₂), 70.3 (C₅H₅), 83.7,

(12) [Fe^ϩ]. Ϫ HR-MS: C₂₁H₃₆B⁵⁶FePS: calcd. 418.171779; found

418.171788.

88.6 (i-C₅H₃R₂). Ϫ EI-MS; m/z: 334.3 (70) [M^ϩ], 245.1 (100) [M^ϩ

H₃CSCHCH₂CH₃], 121.0 (20) [CpFe^ϩ].

HR-MS:

C₁₆H₂₂⁵⁶FeS₂: calcd. 334.051233; found 334.051258.

Ϫ

BH₃-Protected PʜS Ligand 6f: According to GP6, a solution of

hydrazine 5e (189 mg, 0.301 mmol) in CH₂Cl₂(7 mL) was treated SʜS Ligand 6h: According to GP7, a mixture of TFA (2 mL) and

with HBF₄· OEt₂(2.5 equiv.) at 0 °C. After 4 h, a solution of NaBH₄(13.2 equiv.) in CH₂Cl₂(2 mL) was treated with a solution

HBEt₃Li (5.0 equiv., 1  in THF) was added. The reaction mixture

of hydrazine 5g (77 mg, 0.136 mmol) in CH₂Cl₂(2 mL). After

was stirred for 10 min and worked up. Filtration through silica gel

warming to room temperature, the mixture was stirred for 15 h.

(hexane/diethyl ether ϭ 10:1) provided BH₃-protected phosphane Aqueous work up and purification by flash chromatography

6f. Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ Yield: 122 mg (81%, yellow crystals). Ϫ R_fϭ 0.85

(hexane/diethyl ether ϭ 4:1). Ϫ de ϭ 94%. Ϫ ee Ն 96% (¹H NMR:

through silica gel (hexane/diethyl ether ϭ 4:1) provided SʜS ligand

6h. Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hexane/diethyl

ether ϭ 4:1). Ϫ Yield: 44 mg (70%, yellow oil). Ϫ R_fϭ 0.38 (hex-

17 equiv. Pirkle alcohol in C₆D₆, C₅H₅: 3.997 v 4.000 ppm). Ϫ ane/diethyl ether ϭ 4:1). Ϫ Yield: 50 mg (84%, yellow crystals). Ϫ

[α]_D²⁵ϭ Ϫ86.9 (CHCl₃, c ϭ 0.63). Ϫ M.p.: 142 °C. Ϫ IR (CHCl₃): R_fϭ 0.80 (hexane/diethyl ether ϭ 4:1). Ϫ de ϭ 97%. Ϫ ee Ն 99%

ν˜ ϭ 3144 cm^Ϫ1, 3077, 3057, 3006, 2958, 2924, 2863, 2717, 2614, (HPLC: Chiralcel OD-H, cHex, 0.5 mL/min, ent-1: 15.76 min; ent-

2395, 2351, 2264, 1818, 1726, 1600, 1589, 1484, 1450, 1437, 1395,

2: 10.08 min). Ϫ [α]²_D⁵ϭ Ϫ5.9 (CHCl₃, c ϭ 0.46). Ϫ M.p.: 66 °C.

1335, 1312, 1282, 1269, 1245, 1234, 1178, 1148, 1106, 1062, 1043, Ϫ IR (KBr): ν˜ ϭ 3084 cm^Ϫ1, 3017, 2959, 2926, 2863, 2240, 1720,

1029, 1002, 926, 894, 824, 741, 699, 667, 644, 623, 602, 537, 502. 1702, 1686, 1638, 1597, 1563, 1545, 1525, 1492, 1458, 1428, 1407,

Ϫ

¹H NMR (400 MHz, C₆D₆): δ ϭ 0.89 [d, ³J ϭ 6.6 Hz, 3 H, 1377, 1344, 1291, 1246, 1230, 1181, 1147, 1105, 1085, 1052, 1029,

3

1

CH(CH₃)₂], 1.08 [d, ³J ϭ 6.6 Hz, 3 H, CH(CH₃)₂], 1.32 (d, J ϭ

1017, 1001, 939, 918, 882, 841, 805, 747. Ϫ H NMR (300 MHz,

6.6 Hz, 3 H, H₂CCHCH₃), 2.42 (dd, J ϭ 14.0 Hz, J ϭ 11.0 Hz, C₆D₆): δ ϭ 0.94 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.01 (d, ³J ϭ

2

3

1 H, FcCH₂), 2.60 [sept, ³J ϭ 6.6 Hz, 1 H, SCH(CH₃)₂], 2.64 (dqd,

6.7 Hz, 3 H, CHCH₃), 1.03 (d, ³J ϭ 6.7 Hz, 3 H, CHCH₃), 1.51

³J ϭ 11.0 Hz, J ϭ 6.3 Hz, J ϭ 3.3 Hz, 1 H, FcCH₂CH), 3.74 (q, (quint, J ϭ 7.4 Hz, 2 H, CH₂CH₃), 1.99 (s, 3 H, C₆H₄CH₃), 2.33

3

^3/4J ϭ J_HPϭ 2.4 Hz, 1 H, C₅H₃R₂), 3.76 (dd, J ϭ 14.0 Hz, J ϭ (m, 1 H, FcCH₂CH), 2.45 (dd, J ϭ 14.1 Hz, J ϭ 10.4 Hz, 1 H,

2

3

2

3

2

3.6 Hz, 1 H, FcCH₂), 4.01 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.01 (s, FcCH₂), 2.47 (sept, J ϭ 6.7 Hz, 1 H, SCH(CH₃)₂), 3.21 (dd, J ϭ

3422 Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

13.8 Hz, ³J ϭ 4.7 Hz, 1 H, FcCH₂), 4.01 (t, ³J ϭ 2.4 Hz, 1 H, 1498, 1474, 1459, 1433, 1380, 1348, 1325, 1290, 1262, 1228, 1205,

FULL PAPER

3

4

C₅H₃R₂), 4.02 (s, 5 H, C₅H₅), 4.39 (dd, J ϭ 2.4 Hz, J ϭ 1.4 Hz,

1179, 1147,1104, 1070, 1052, 1024, 1002, 955, 918, 835, 813, 743,

723, 699. Ϫ H NMR (400 MHz, C₆D₆): δ ϭ 0.90 (t, J ϭ 7.4 Hz,

3

4

1

3

1 H, C₅H₃R₂), 4.53 (dd, J ϭ 2.4 Hz, J ϭ 1.3 Hz, 1 H, C₅H₃R₂),

6.83 (d, ³J ϭ 8.1 Hz, 2 H, C₆H₄), 7.17 (dt, ³J ϭ 8.1 Hz, ⁴J ϭ 2.0 Hz, 3 H, CH₂CH₃), 1.45 (m, 2 H, CH₂CH₃), 1.66 (s, 3 H, SCH₃), 2.16

2 H, C₆H₄). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 11.3, 20.8, 23.9, (dtd, ³J ϭ 10.4 Hz, ³J ϭ 6.3 Hz, ³J ϭ 4.1 Hz, 1 H, SCH), 2.55 (dd,

24.2 (CH₃), 30.0 (CH₂CH₃), 34.9 [SCH(CH₃)₂], 35.6 (FcCH₂), 48.8 ²J ϭ 14.3 Hz, ³J ϭ 10.4 Hz, 1 H, FcCH₂), 3.33 (ddd, ²J ϭ 14.3 Hz,

(SCHCH₂), 68.5, 72.4, 75.4 (C₅H₃R₂), 70.5 (C₅H₅), 90.6 (i-

³J ϭ 3.9 Hz, ⁴J_HPϭ 3.0 Hz, 1 H, FcCH₂), 3.82 (m, 1 H, C₅H₃R₂),

3

C₅H₃R₂), 127.1, 129.7 (C₆H₄), 138.9 (i-C₆H₄). Ϫ EI-MS; m/z: 438.3 3.91 (s, 5 H, C₅H₅), 4.10 (t, J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.53 (td,

(68) [M^ϩ], 321.2 (100) [M^ϩϪ (H₃C)₂CHSCHCH₂CH₃], 319.2 (17) ³J ϭ J_HPϭ 2.2 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂), 6.96Ϫ7.10 (m, 6

4

[321.2 Ϫ H₂], 272.1 (16), 255.1 (34) [321.2 Ϫ C₅H₆], 199.2 (20)

[255.1 Ϫ Fc], 165.1 (13), 153.1 (11), 121.1 (25) [CpFe^ϩ], 115.1 (10),

91.2 (11) [C₇H₇^ϩ], 75.2 (14) [(H₃C)₂CHS^ϩ], 56.1 (15) [Fe^ϩ]. Ϫ HR-

MS: C₂₄H₃₀⁵⁶FeS₂: calcd. 438.113833; found 438.113712.

H, m/p-C₆H₅), 7.39 (tt, J ϭ 6.6 Hz, ⁴J ϭ 1.7 Hz, 2 H, o-C₆H₅),

7.65 (m, 2 H, o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 10.8,

12.7 (CH₃), 27.8 (CH₂CH₃), 34.4 (d, ³J_CPϭ 10.3 Hz, FcCH₂), 50.6

(SCH), 69.0, 70.6, 73.3 (d, J_CPϭ 4.0 Hz, C₅H₃R₂), 69.5 (C₅H₅),

2

91.6 (i-C₅H₃R₂), 132.6 (d, J_CPϭ 18.9 Hz), 134.8 (d, J_CP

ϭ

21.2 Hz, o-C₆H₅). Ϫ ³¹P NMR (C₆D₆, 162 MHz): Ϫ25.0 (s). Ϫ EI-

MS; m/z: 472.1 (66) [M^ϩ], 457.1 (100) [M^ϩϪ CH₃], 424.2 (19) [M^ϩ

Ϫ HSCH₃], 391.1 (11), 240.1 (62), 184.1 (35), 121.0 (15) [CpFe^ϩ],

56.1 (11) [Fc^ϩ]. Ϫ HR-MS: C₂₇H₂₉⁵⁶FePS: calcd. 472.107699;

found 472.107765.

SʜSe Ligand 6i: According to GP7, a mixture of TFA (86 µL) and

NaBH₄(10 equiv.) in CH₂Cl₂(3 mL) was treated with a solution

of hydrazine 5h (134 mg, 0.224 mmol) in CH₂Cl₂(2 mL). After

warming to room temperature, a further portion of NaBH₄(10

equiv.) was added and stirring was continued for 15 h. Afterwards,

a further portion of TFA (172 µL) was added. The mixture was

stirred for a further 6 h. Aqueous workup and purification by flash

chromatography through silica gel (hexane/diethyl ether ϭ 4:1) pro-

PʜS Ligand 6k: a) According to GP8, a solution of BH₃-protected

phosphane 6c (75 mg, 0.159 mmol) in diethyl ether (4 mL) was

vided SʜSe ligand 6i. Ϫ Yield: 74 mg (70%, yellow crystals). Ϫ treated with TMEDA (5.0 equiv.) for 5 h at room temperature. Fil-

R_fϭ 0.80 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ ee Ն 99%

(HPLC: Chiralcel OD-2, cHex, 0.5 mL/min, ent-1: 14.36 min; ent-

tration through silica gel under argon (hexane/diethyl ether ϭ 10:1)

provided PʜS ligand 6k. b) A heated Schlenk flask was charged

2: 10.55 min). Ϫ [α]²_D⁵ϭ Ϫ8.0 (CHCl₃, c ϭ 0.44). Ϫ M.p.: 59 °C. under argon with a solution of hydrazine 5b (79 mg, 0.132 mmol)

Ϫ IR (CHCl₃): ν˜ ϭ 3094 cm^Ϫ1, 3071, 3058, 2958, 2925, 2858, 1728,

1641, 1579, 1477, 1460, 1439, 1380, 1366, 1342, 1290, 1261, 1244,

in CH₂Cl₂(4 mL) at 0 °C. After HBF₄OEt₂(2.5 equiv.) was added,

the solution was stirred for 45 min. nBuLi (5.0 equiv.) and benzyla-

1219, 1178, 1155, 1125, 1106, 1070, 1051, 1023, 1001, 973, 921, 875, mine (0.3 mL) were added successively. After 1 h, the reaction mix-

821, 758, 735, 691, 668, 526, 506, 496, 465. Ϫ ¹H NMR (300 MHz,

ture was worked up according to GP6 and the product 6k was

C₆D₆): δ ϭ 0.94 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 0.98 (d, ³J ϭ obtained by filtration through silica gel (hexane/diethyl ether ϭ

6.6 Hz, 3 H, CHCH₃), 1.00 (d, ³J ϭ 6.9 Hz, 3 H, CHCH₃), 1.51 10:1). Ϫ Yield: a) 37 mg (51%, yellow crystals); b) 40 mg (66%). Ϫ

(m, 2 H, CH₂CH₃), 2.21 (dtd, ³J ϭ 10.2 Hz, ³J ϭ 6.3 Hz, ³J ϭ R_fϭ 0.73 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵

ϭ

3.8 Hz, 1 H, FcCH₂CH), 2.43 [sept, ³J ϭ 6.6 Hz, 1 H, SCH(CH₃)₂],

Ϫ240.9 (CHCl₃, c ϭ 1.40). Ϫ Mp: 98 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3180

2.43 (dd, ²J ϭ 14.0 Hz, ³J ϭ 10.2 Hz, 1 H, FcCH₂), 3.16 (dd, ²J ϭ cm^Ϫ1, 3078, 3058, 2968, 2927, 2857, 1723, 1591, 1483, 1438, 1400,

14.0 Hz, ³J ϭ 3.9 Hz, 1 H, FcCH₂), 3.99 (s, 5 H, C₅H₅), 4.02 (t, 1377, 1312, 1266, 1238, 1216, 1188, 1173, 1161, 1120, 1108, 1083,

3

4

1

³J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.38 (dd, J ϭ 2.2 Hz, J ϭ 1.4 Hz, 1

1043, 1001, 948, 826, 756, 723, 702, 665, 573, 544, 508, 459. Ϫ H

H, C₅H₃R₂), 4.50 (dd, ³J ϭ 2.7 Hz, ⁴J ϭ 1.4 Hz, 1 H, C₅H₃R₂), NMR (300 MHz, C₆D₆): δ ϭ 1.10 (d, J ϭ 6.9 Hz, 3 H, CHCH₃),

3

6.86 (tt, ³J ϭ 7.2 Hz, ⁴J ϭ 1.4 Hz, 1 H, p-C₆H₅), 6.92 (tm, ³J ϭ 1.68 (s, 3 H, SCH₃), 2.43 (dqd, ³J ϭ 9.5 Hz, ³J ϭ 6.9 Hz, ³J ϭ

3

4

7.4 Hz, 2 H, m-C₆H₅), 7.33 (dd, J ϭ 8.0 Hz, J ϭ 1.1 Hz, 2 H, o-

C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 11.3, 23.9, 24.2 (CH₃), FcCH₂), 3.24 (ddd, J ϭ 14.0 Hz, ³J ϭ 4.7 Hz, J_HPϭ 2.8 Hz, 1

4.7 Hz, 1 H, SCH), 2.57 (dd, ²J ϭ 14.0 Hz, ³J ϭ 9.9 Hz, 1 H,

2

4

30.0 (CH₂CH₃), 35.0 [SCH(CH₃)₂], 36.6 (FcCH₂), 49.0 (SCHCH₂),

H, FcCH₂), 3.84 (m, 1 H, C₅H₃R₂), 3.88 (s, 5 H, C₅H₅), 4.09 (t,

69.4, 72.3, 76.5 (C₅H₃R₂), 70.3 (C₅H₅), 91.0 (i-C₅H₃R₂), 126.0 (p- ³J ϭ 2.4 Hz, 1 H, C₅H₃R₂), 4.44 (td, ³J ϭ J_HPϭ 2.5 Hz, ⁴J ϭ

C₆H₅), 129.2, 129.6 (o/m-C₆H₅), 135.7 (i-C₆H₅). Ϫ EI-MS; m/z: 1.4 Hz, 1 H, C₅H₃R₂), 6.95Ϫ7.11 (m, 6 H, m/p-C₆H₅), 7.39 (ddd,

472.2 (100) [M^ϩ], 355.1 (58) [M^ϩϪ (H₃C)₂CHSCHCH₂CH₃], J ϭ 8.3 Hz, J ϭ 6.9 Hz, J ϭ 1.9 Hz, 2 H, o-C₆H₅), 7.66 (m, 2 H,

4

289.1 (27) [355.1 Ϫ C₅H₆], 275.1 (13), 272.2 (22), 199.1 (10)

o-C₆H₅). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.4 (SCH₃), 22.1

[FcCH₂^ϩ], 141.0 (12), 121.1 (13) [CpFe^ϩ], 57.3 (10) [FeH^ϩ]. Ϫ HR- (CHCH₃), 37.4 (d, J_CPϭ 9.7 Hz, FcCH₂), 44.1 (SCH), 69.7, 71.3

3

MS: C₂₃H₂₈⁵⁶FeSSe calcd. 472.042632; found 472.042739.

(d, J_CPϭ 4.6 Hz), 73.6 (d, J_CPϭ 4.0 Hz, C₅H₃R₂), 70.1 (C₅H₅),

2

91.6 (i-C₅H₃R₂), 128.9, 129.2 (p-C₆H₅), 132.9 (d, J_CPϭ 18.4 Hz),

135.5 (d, ²J_CPϭ 21.2 Hz, o-C₆H₅). Ϫ ³¹P NMR (C₆D₆, 162 MHz):

Ϫ24.7 (s). Ϫ EI-MS; m/z: 474.2 (100) [MO^ϩ], 427.1 (83) [474.2 Ϫ

SCH₃], 399.2 (14) [474.2 Ϫ H₃CCHSCH₃], 361.1 (35) [427.1 Ϫ

CpH], 333.1 (25) [399.2 Ϫ CpH], 226.2 (19) [427.1 Ϫ Ph₂PO], 57.1

(10) [FeH^ϩ]. Ϫ HR-MS: C₂₆H₂₇⁵⁶FePS: calcd. 458.092049; found

458.092033.

PʜS Ligand 6j: a) According to GP8, a solution of BH₃-protected

phosphane 6d (83 mg, 0.171 mmol) in diethyl ether (5 mL) was

treated with TMEDA (5.0 equiv.) for 5 h at room temperature. Fil-

tration through silica gel under argon (hexane/diethyl ether ϭ 10:1)

provided PʜS ligand 6j. b) A heated Schlenk flask was charged

under argon with a solution of hydrazine 5c (65 mg, 0.106 mmol)

in CH₂Cl₂(4 mL) at 0 °C. After HBF₄OEt₂(2.5 equiv.) was added,

the solution was stirred for 45 min. nBuLi (5.0 equiv.) and benzyla-

mine (0.1 mL) were added successively. After 1 h, the reaction mix-

PʜS Ligand 6l: According to GP8, a solution of BH₃-protected

phosphane 6e (87 mg, 0.210 mmol) in toluene (6 mL) was treated

ture was worked up according to GP6 and the product 6j was ob- with TMEDA (10.0 equiv.) for 15 h at 90 °C. Filtration through

tained by filtration through silica gel (hexane/diethyl ether ϭ 10:1). silica gel under argon (hexane/diethyl ether ϭ 10:1) provided PʜS

Ϫ Yield: a) 71 mg (88%, yellow crystals); b) 36 mg (68%). Ϫ R_fϭ ligand 6l. Ϫ Yield: 80 mg (95%, orange oil). Ϫ R_fϭ 0.80 (hexane/

0.71 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ Ϫ263.1

(CHCl₃, c ϭ 0.64). Ϫ M.p.: 107 °C. Ϫ IR (CHCl₃): ν˜ ϭ 3050 cm^Ϫ1

2962, 2925, 2855, 2183, 1900, 1719, 1686, 1656, 1638, 1584, 1545,

diethyl ether ϭ 4:1). Ϫ de ϭ 97%. Ϫ [α]²_D⁵ϭ Ϫ83.4 (CHCl₃, c ϭ

1.69). Ϫ IR (CHCl₃): ν˜ ϭ 3095 cm^Ϫ1, 2954, 2920 (v), 2866, 1641,

1440, 1382, 1363, 1294, 1231, 1176, 1153, 1107, 1072, 1039, 1021,

,

Eur. J. Org. Chem. 2000, 3399Ϫ3426

3423

D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink, J. W. Bats

FULL PAPER

3

4

1002, 956, 927, 880, 819, 753, 700, 661, 632, 599, 572, 493, 475. Ϫ 1 H, C₅H₃R₂), 4.18 (dd, J ϭ 2.5 Hz, J ϭ 1.4 Hz, 1 H, C₅H₃R₂),

3

¹H NMR (300 MHz, C₆D₆): δ ϭ 0.88 (dd, J_HPϭ 12.9 Hz, J ϭ 7.04Ϫ7.14 (m, 6 H, m/p-C₆H₅), 7.61 (m, 4 H, o-C₆H₅). Ϫ ¹³C NMR

3

2

7.2 Hz, 3 H, PCHCH₃), 1.04 (dd, J_HPϭ 13.5 Hz, J ϭ 6.9 Hz, 3

(75 MHz, C₆D₆): δ ϭ 16.9 (d, J_CPϭ 14.3 Hz, CHCH₃), 20.2

H, PCHCH₃), 1.12 (t, ³J ϭ 7.4 Hz, 3 H, CH₂CH₃), 1.26 (dd, (SCH₃), 32.6 (d, J_CPϭ 22.3 Hz, PCH), 33.3 (d, J_CPϭ 12.0 Hz,

1

2

³J_HPϭ 9.1 Hz, ³J ϭ 7.1 Hz, 3 H, PCHCH₃), 1.42 (dd, J_HP

ϭ

FcCH₂), 67.3, 68.9, 71.4 (C₅H₃R₂), 70.4 (C₅H₅), 84.3, 89.7 (d,

3

16.5 Hz, ³J ϭ 7.7 Hz, 3 H, PCHCH₃), 1.55Ϫ1.85 (m, 3 H,

J_CPϭ 14.9 Hz, C₅H₃R₂), 128.6Ϫ129.0 (m/p-C₆H₅), 133.8 (d,

CH₂CH₃, PCH), 1.79 (s, 3 H, SCH₃), 2.26 (septd, ³J ϭ 7.2 Hz, ²J_CPϭ 18.9 Hz), 134.3 (d, J_CPϭ 19.5 Hz, o-C₆H₅), 137.9 (d,

2

²J_HPϭ 3.8 Hz, 1 H, PCH), 2.67 (m, 1 H, FcCH₂), 2.71 (dd, J ϭ ¹J_CPϭ 16.1 Hz), 138.4 (d, J_CPϭ 15.5 Hz, i-C₆H₅). Ϫ ³¹P NMR

2

1

3

22.5 Hz, J ϭ 9.1 Hz, 1 H, FcCH₂), 3.12 (dm, J ϭ 12.6 Hz, 1 H,

(C₆D₆, 162 MHz): Ϫ0.3 (s). Ϫ EI-MS; m/z: 458.1 (57) [M^ϩ], 443.1

SCH), 3.96 (dd, J ϭ 2.5 Hz, J ϭ 1.1 Hz, 1 H, C₅H₃R₂), 4.00 (s, (100) [M^ϩϪ CH₃], 411.1 (21) [M^ϩϪ SCH₃], 393.1 (52) [M^ϩ

5 H, C₅H₅), 4.09 (t, ³J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.54 (m, 1 H, C₅H₅], 290.0 (34) [411.1 Ϫ CpFe], 225.9 (19) [H₃CC(PPh₂)ϭCH₂^ϩ].

C₅H₃R₂). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 11.7, 13.0 (CH₂CH₃, Ϫ HR-MS: C₂₆H₂₇⁵⁶FePS: calcd. 458.092049; found 458.091418.

3

4

Ϫ

2

SCH₃), 19.6 (d, J_CPϭ 4.5 Hz), 21.2 (d, J_CPϭ 13.7 Hz), 25.8 (d,

²J_CPϭ 5.7 Hz), 25.9 (d, J_CPϭ 5.7 Hz, PCHCH₃), 20.8 (d, J_CPϭ

2

1

SʜS Ligand 13: According to GP7, a mixture of TFA (1 mL) and

NaBH₄(13.2 equiv.) in CH₂Cl₂(4 mL) was treated with a solution

of hydrazine 12 (78 mg, 0.126 mmol) in CH₂Cl₂(2 mL). After

warming to room temperature, the mixture was stirred for 15 h.

Aqueous work up and purification by flash chromatography

through silica gel (hexane/diethyl ether ϭ 10:1) provided SʜS li-

gand 13. Ϫ Yield: 27 mg (59%, yellow oil). Ϫ R_fϭ 0.48 (hexane/

diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ78.8 (CHCl₃, c ϭ

0.25). Ϫ IR (CHCl₃): ν˜ ϭ 3086 cm^Ϫ1, 2960, 2918, 2865, 1727, 1658,

1631, 1450, 1437, 1397, 1373, 1313, 1279, 1229, 1173, 1098, 1053,

1

17.1 Hz), 23.3 (d, J_CPϭ 24.1 Hz, PCH), 28.4 (CH₂CH₃), 35.1 (d,

³J_CPϭ 10.9 Hz, FcCH₂), 50.6 (SCH), 68.9, 70.2 (d, J_CPϭ 4.3 Hz),

2

71.4 (d, J_CPϭ 4.0 Hz, C₅H₃R₂), 70.0 (C₅H₅), 79.9 (d, J_CP

ϭ

24.0 Hz), 92.2 (d, J_CPϭ 24.0 Hz, i-C₅H₃R₂). Ϫ ³¹P NMR (C₆D₆,

162 MHz): Ϫ9.0 (s). Ϫ EI-MS; m/z: 404.2 (19) [M^ϩ], 389.1 (100)

[M^ϩϪ CH₃], 357.2 (13) [M^ϩϪ SCH₃], 271.1 (11) [389.1 Ϫ

HP(iPr)₂], 240.0 (35) [357.2 Ϫ P(iPr)₂]. Ϫ HR-MS: C₂₁H₃₃⁵⁶FePS:

calcd. 404.138999; found 404.138757.

1

PʜS Ligand 6m: According to GP8, a solution of BH₃-protected

phosphane 6f (122 mg, 0.244 mmol) in diethyl ether (6 mL)/toluene

(4 mL) was treated with TMEDA (5.0 equiv.) for 8 h at room tem-

perature. Filtration through silica gel under argon (hexane/diethyl

ether ϭ 10:1) provided PʜS ligand 6m. Ϫ Yield: 108 mg (91%,

1040, 1023, 955, 928, 880, 855, 825, 808, 757, 532, 509, 494. Ϫ H

NMR (300 MHz, C₆D₆): δ ϭ 1.15 (d, ³J ϭ 6.6 Hz, 6 H, CH₃), 1.81

2

(s, 6 H, SCH₃), 2.38 (dd, J ϭ 13.5 Hz, ³J ϭ 8.2 Hz, 2 H, FcCH₂),

2.52 (dqd, ³J ϭ 8.2 Hz, ³J ϭ 6.6 Hz, ³J ϭ 5.2 Hz, 2 H, SCH), 2.71

(dd, ²J ϭ 13.5 Hz, ³J ϭ 5.2 Hz, 2 H, FcCH₂), 3.90 (m, 8 H,

yellow crystals). Ϫ R_fϭ 0.90 (hexane/diethyl ether ϭ 4:1). Ϫ de Ն C₅H₄R). Ϫ ¹³C NMR (75 MHz, C₆D₆): δ ϭ 13.8 (SCH₃), 20.5

96%. Ϫ [α]²_D⁵ϭ Ϫ186.0(CHCl₃, c ϭ 1.21). Ϫ Mp: 116 °C. Ϫ IR

(CH₃), 37.9 (FcCH₂), 43.5 (SCH), 68.6, 68.8, 70.0, 70.4 (C₅H₃R₂),

(CHCl₃): ν˜ ϭ 3068 cm^Ϫ1, 2960, 2922, 2864, 1661, 1586, 1435, 1380, 86.1 (i-C₅H₃R₂). Ϫ EI-MS; m/z: 362.1 (100) [M^ϩ], 240.2 (24), 209.0

1327, 1309, 1266, 1237, 1179, 1155, 1104, 1071, 1030, 1002, 880, (49), 161.0 (35), 135.0 (8). Ϫ HR-MS: C₁₈H₂₆⁵⁶FeS₂: calcd.

818, 748, 699, 667, 641, 573, 500, 454. Ϫ ¹H NMR (400 MHz,

C₆D₆): δ ϭ 0.99 (d, J ϭ 6.6 Hz, 3 H), 1.10 (d, J ϭ 6.6 Hz, 3 H),

1.17 (d, J ϭ 6.6 Hz, 3 H, CH₃), 2.58Ϫ2.70 [m, 3 H, SCH(CH₃)₂,

362.082533; found 362.082403.

3

Pd؊PʜS Complex 20: Bis[µ-Chloro(η³-PhCHCHCHPh)palladiu-

m(II)] (38 mg, 0.056 mmol) was added to a solution of ligand 6j

(53 mg, 0.112 mmol) in acetone (10 mL). After stirring for 30 min

at room temperature, TlPF₆(39 mg, 0.112 mmol) was added. After

3

FcCH₂CH, FcCH₂], 3.29 (dt, ²J ϭ 12.9 Hz, ³J ϭ ⁴J_HPϭ 3.0 Hz, 1

H, FcCH₂), 3.85 (m, 1 H, C₅H₃R₂), 3.86 (s, 5 H, C₅H₅), 4.08 (t,

³J ϭ 2.5 Hz, 1 H, C₅H₃R₂), 4.53 (td, ³J ϭ J_HPϭ 2.2 Hz, ⁴J ϭ

1.4 Hz, 1 H, C₅H₃R₂), 6.99Ϫ7.10 (m, 6 H, m/p-C₆H₅), 7.40 (tt, J ϭ

7.1 Hz, J ϭ 1.4 Hz, 2 H, o-C₆H₅), 7.67 (m, 2 H, o-C₆H₅). Ϫ ¹³C

NMR (100 MHz, C₆D₆): δ ϭ 23.3, 23.8, 24.0 (CH₃), 38.1 (d,

1 h, the mixture was decanted and TlCl filtered off (Celite). The

1

solution was concentrated to

/ under a stream of argon and n-

4

pentane (30 mL) was added, causing deposition of a dark red oil.

The pure compound was obtained in 97% yield after crystallization

from CH₂Cl₂/Et₂O at Ϫ26 °C. Ϫ Yield: 100 mg (97%, red-brown

crystals). Ϫ dr ϭ 86:9:3:2. Ϫ [α]²_D⁵ϭ ϩ42.6 (CHCl₃, c ϭ 0.66). Ϫ

M.p.: 88 °C. Ϫ IR (KBr): ν˜ ϭ 3055 cm^Ϫ1, 2964, 2928, 2873, 1543,

1491, 1462, 1436, 1386, 1316, 1250, 1186, 1157, 1100, 1001, 913,

839, 757, 730, 695, 648, 558, 514, 485, 468. Ϫ ¹H NMR (500 MHz,

C₆D₆): δ ϭ 1.05 (t, ³J ϭ 7.3 Hz, 3 H, CH₂CH₃), 1.11 (s, 3 H,

SCH₃), 1.48Ϫ1.61 (m, 2 H, CH₂CH₃), 2.94 (tdd, ³J ϭ 7.3 Hz, ³J ϭ

4.7 Hz, ³J ϭ 2.6 Hz, 1 H, SCH), 3.26 (dd, ²J ϭ 15.7 Hz, ³J ϭ

³J_CPϭ 10.8 Hz, FcCH₂), 41.4 (SCH), 69.7, 71.2 (d, J_CPϭ 4.1 Hz),

73.6 (d, J_CPϭ 4.0 Hz, C₅H₃R₂), 70.0 (C₅H₅), 76.2 (d, J_CP

2

ϭ

1

7.4 Hz), 92.3 (d, J_CPϭ 27.5 Hz, C₅H₃R₂), 128.4, 129.1 (m-C₆H₄),

133.0 (d, ²J_CPϭ 18.3 Hz), 135.5 (d, ²J_CPϭ 21.8 Hz, o-C₆H₅), 138.6

(d, ¹J_CPϭ 9.2 Hz), 141.3 (d, ¹J_CPϭ 10.3 Hz, i-C₆H₄). Ϫ ³¹P NMR

(C₆D₆, 162 MHz): Ϫ23.7 (s). Ϫ EI-MS; m/z: 502.2 (51) [MO^ϩ],

486.3 (12) [M^ϩ], 443.2 (100) [M^ϩϪ CH(CH₃)₂], 427.1 (29) [443.2

Ϫ

CH₄], 226.0 (46) [FcϪCHϭCHϪCH₃^ϩ].

C₂₈H₃₁⁵⁶FePS: calcd. 486.123349; found 486.123023.

Ϫ

HR-MS:

2

2.6 Hz, 1 H, FcCH₂), 3.61 (s, 5 H, C₅H₅), 3.87 (dd, J ϭ 15.4 Hz,

3

PʜS Ligand 6n: According to GP8, a solution of BH₃-protected

phosphane 6a (70 mg, 0.148 mmol) in toluene (5 mL) was treated

with TMEDA (10.0 equiv.) for 20 h at 90 °C. Filtration through

silica gel under argon (hexane/diethyl ether ϭ 10:1) provided PʜS

ligand 6n. Ϫ Yield: 40 mg (59%, yellow oil). Ϫ R_fϭ 0.52 (hexane/

³J ϭ 4.3 Hz, 1 H, FcCH₂), 4.03 (dt, ³J ϭ 2.6 Hz, ⁴J ϭ J_HP

ϭ

1.3 Hz, 1 H, PCCH_Cp), 4.37 (t, ³J ϭ 2.5 Hz, 1 H, PCCHCH_Cp),

4.40 (td, J ϭ J_HPϭ 2.4 Hz, J ϭ 1.2 Hz, PCCHCHCH_Cp), 5.17

(d, J ϭ 9.6 Hz, 1 H, C₆H₅CH trans to S), 6.27 (d, J ϭ 13.5 Hz,

1 H, C₆H₅CH trans to P), 6.32 (dd, J ϭ 13.5 Hz, J ϭ 9.5 Hz, 1

3

4

3

diethyl ether ϭ 4:1). Ϫ de Ն 96%. Ϫ [α]²_D⁵ϭ ϩ67.9 (CHCl₃, c ϭ H, C₆H₅CHCH), 6.40 (ddd, J_HPϭ 9.6 Hz, ³J ϭ 8.4 Hz, ⁴J ϭ

3

1.03). Ϫ IR (CHCl₃): ν˜ ϭ 3071 cm^Ϫ1, 3053, 2964, 2919, 2866, 1585, 1.2 Hz, 2 H, PϪo-C₆H_5up), 6.93 (dm, J ϭ 8.2 Hz, 2 H, CH trans

3

1480, 1434, 1375, 1312, 1218, 1183, 1159, 1118, 1106, 1096, 1071, to SϪo-C₆H₅), 6.99 (t, J ϭ 7.5 Hz, 2 H, CH trans to SϪm-C₆H₅),

1

3

1028, 1000, 967, 889, 863, 821, 754, 722, 698, 666, 536, 509. Ϫ H

7.10 (tm, J ϭ 8.2 Hz, 2 H, PϪm-C₆H_5up), 7.18 (tq, J ϭ 7.3 Hz,

NMR (300 MHz, C₆D₆): δ ϭ 1.11 (dd, J_HPϭ 14.0 Hz, ³J ϭ ⁴J ϭ J_HPϭ 1.4 Hz, 1 H, CH trans to SϪp-C₆H₅), 7.30 (tq, J ϭ

3

4

5

6.9 Hz, 3 H, CHCH₃), 1.98 (s, 3 H, SCH₃), 2.53 (m, 1 H, PCH), 7.5 Hz, J ϭ J_HPϭ 1.4 Hz, 1 H, PϪp-C₆H_5up), 7.38 (m, 3 H, CH

2

3

2.89 (t, J ϭ J ϭ 8.2 Hz, 2 H, FcCH₂), 3.90 (s, 5 H, C₅H₅), 3.91

trans to PϪm-C₆H₅, CH trans to PϪp-C₆H₅), 7.54 (tdt, ³J ϭ

(t, ³J ϭ 2.8 Hz, 1 H, C₅H₃R₂), 4.06 (dd, J ϭ 2.5 Hz, ⁴J ϭ 1.4 Hz, 7.5 Hz, ⁵J_HPϭ 2.1 Hz, ⁴J ϭ 1.1 Hz, 1 H, PϪp-C₆H_5down), 7.59 (tdt,

3

3424

Eur. J. Org. Chem. 2000, 3399Ϫ3426

Asymmetric Synthesis of Novel Ferrocenyl Ligands with Planar and Central Chirality

FULL PAPER

4

³J ϭ 7.2 Hz, J_HPϭ 2.3 Hz, ⁴J ϭ 1.6 Hz, 2 H, PϪm-C₆H_5down),

ing structure factors) for structure 5e are stored as supplementary

7.69 (dm, ³J ϭ 6.7 Hz, 2 H, CH trans to PϪo-C₆H₅), 7.85 (ddd, publication no. CCDC-116942 at the Cambridge Crystallographic

³J_HPϭ 12.4 Hz, ³J ϭ 8.2 Hz, ⁴J ϭ 1.4 Hz, 2 H, PϪo-C₆H_5down). Ϫ

Data Centre. Copies of these data can be ordered free of

¹³C NMR (125 MHz, C₆D₆): δ ϭ 12.1 (SCH₃), 12.2 (CH₃), 23.9 charge at the following address: CCDC, 12 Union Road,

(CH₂CH₃), 32.6 (FcCH₂), 53.4 (SCH), 70.5 (PCCHCH_Cp), 70.9 Cambridge CB21EZ [Fax: (internat.) ϩ 44-1223/336-033; E-mail:

(C₅H₅), 73.0 (PCCH_Cp), 78.2 (C₆H₅CH trans to S), 102.4 (d, ²J_CPϭ

20.3 Hz, C₆H₅CH trans to P), 109.2 (C₆H₅CHCH), 127.7 (CH trans

to SϪp-C₆H₅), 128.1 (d, J_CPϭ 9.3 Hz, PϪm-C₆H_5up), 128.4 (CH

trans to SϪo-C₆H₅), 128.6 (CH trans to P-o-C₆H₅, CH trans to

SϪm-C₆H₅), 128.9 (d, ³J_CPϭ 11.5 Hz, PϪm-C₆H_5down), 129.7 (CH

trans to PϪm/p-C₆H₅), 129.9 (PϪp-C₆H_5up), 131.0 (PϪi-C₆H_5up),

deposit@ccdc.cam.ac.uk].

X-ray Structure Analysis of 20: C₄₂H₄₂FePPdS^ϩPF₆^Ϫ· CH₂Cl₂;

3

M_rϭ 1002; orthorhombic, P2₁2₁2₁; a ϭ 10.239(1), b ϭ 19.986(4),

3

c ϭ 20.559(3) A; V ϭ 4207(1) A ; Z ϭ 4; D_xϭ 1.582 g cm^Ϫ3

;

˚

µ(Mo-K_α) ϭ 1.083 mm^Ϫ1; 147 K. Structure refinement with

SHELXL-97; H atoms riding; final R ϭ 0.061 for 9445 observed

reflections. Crystallographic data (without structure factors) have

been deposited with the Cambridge Crystallographic Data Centre

as supplementary publication no. CCDC-135357. Copies of the

data can be obtained, free of charge, on application to CCDC,

12 Union Road, Cambridge CB2 1EZ, UK [Fax: (internat.)

ϩ 44-1223/336-033; E-mail: deposit@ccdc.cam.ac.uk].

2

131.2 (PϪp-C₆H_5down), 131.9 (d, J_CPϭ 10.4 Hz, PϪo-C₆H_5up),

132.8 (PϪi-C₆H_5down), 134.4 (d, J_CPϭ 14.2 Hz, PϪo-C₆H_5up),

2

136.2 (CH trans to SϪi-C₆H₅), 137.0 (CH trans to PϪi-C₆H₅). Ϫ

³¹P NMR (C₆D₆, 162 MHz): Ϫ143.0 (sept, J_PFϭ 714.9 Hz,

1

PF₆^Ϫ), ϩ15.2 (s, PPh₂). Ϫ EI-MS; m/z: 472.1 (43) [M^ϩ

Ϫ

Pd(PhCHCHCHPh)], 457.1 (80) [472.1 Ϫ CH₃], 425.3 (10) [472.1

SCH₃], 240.2 (100) [425.2 PPh₂], 193.2 (68)

[PhCHCHCHPh^ϩ], 183.1 (49) [PPh₂Ϫ H₂], 165.2 (15), 152.2 (11),

121.0 (28) 115.2 (43), 107.2 (26).

[CpFe^ϩ],

C₄₂H₄₂F₆FeP₂PdS · CH₂Cl₂(1002): calcd. C 50.35, H 4.43; found

C 50.61, H 4.41.

Ϫ

Acknowledgments

This work was supported by the Deutsche Forschungsgemeinschaft

(Leibniz-Preis), the Fonds der Chemischen Industrie, and the For-

schungsverbund Katalyse Nordrhein-Westfalen. We thank De-

gussa-Hüls AG, BASF AG, the former Hoechst AG, Bayer AG,

and Wacker Chemie for the donation of chemicals.

Malonate (R)-17: A mixture of (π-allyl)palladium(II) chloride

dimer (3.7 mg, 0.01 mmol) and ligand 6j (10.4 mg, 0.022 mmol) in

CH₂Cl₂(1.5 mL) was stirred at room temperature for 1 h. The solu-

tion was cooled to Ϫ20 °C and acetate 16 (1.0 mmol, 252 mg) in

CH₂Cl₂(0.5 mL) was added, followed sequentially by dimethyl ma-

lonate (3.0 equiv., 0.34 mL), N,O-bis(trimethylsilyl)acetamide

(BSA, 3.0 equiv., 0.74 mL), and KOAc (1 mg). After 24 h at Ϫ20

°C, the reaction mixture was diluted with Et₂O (20 mL), quenched

with saturated aqueous NH₄Cl (20 mL), and washed with saturated

brine (20 mL). The organic layer was dried with MgSO₄. After

evaporation of the solvent in vacuo, the crude product was purified

by column chromatography (hexane/diethyl ether ϭ 4:1). Ϫ Yield:

321 mg (99%, colourless oil). Ϫ ee ϭ 97% [¹H NMR, Eu(tfc)₃,

CDCl₃]. Ϫ [α]²_D⁵ϭ ϩ20.0 (EtOH, c ϭ 1.05).

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˚

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Article Doi

Asymmetric synthesis of novel ferrocenyl ligands with planar and central chirality and their application to Pd-catalyzed allylic substitutions

DOI: 10.1002/1099-0690(200010)2000:20<3399::aid-ejoc3399>3.0.co;2-d

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