High diastereoselective Michael and aldol additions of Fischer-type alkyl(hydrazino)carbene complexes: Synthesis of new hydrazides

Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

www.elsevier.com/locate/jorganchem

High diastereoselective Michael and aldol additions of Fischer-type

alkyl(hydrazino)carbene complexes: synthesis of new hydrazides

Emanuela Licandro ^a,*, Dario Perdicchia ^a, Stefano Maiorana ^a, Clara Baldoli ^a,

Clelia Giannini ^a, Claudia Graiff ^b, Antonio Tiripicchio ^b

^aDipartimento di Chimica Organica e Industriale, CNR-Istituto di Scienze e Tecnologie Molecolari and Centro di Eccellenza CISI,

Universita` degli Studi di Milano, Via C. Golgi, 19, I-20133 Milan, Italy

^bDipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Universita` di Parma, Parco Area delle Scienze 17/A,

I-43100 Parma, Italy

Received 19 March 2003; received in revised form 10 April 2003; accepted 9 May 2003

Dedicated with admiration to Professor Ernst Otto Fischer on the occasion of his 85th birthday

Abstract

The addition of the enolate, generated from the tetracarbonylethyl(hydrazino)carbene chromium complex 6, to achiral enones

and aldehydes gave the corresponding Michael and aldol adducts in very high chemical yield and d.e.. Some of the new d-keto and b-

hydroxy hydrazino carbene complexes have been oxidised to give the corresponding hydrazides in high yield. A spectroscopic study

to establish the geometry of the enolate generated from 6 has also been performed.

Keywords: Fischer-type hydrazinocarbenes; Hydrazides; Stereoselective Michael addition; Stereoselective aldol addition; Oxidation of Fischer

complexes

1. Introduction

pounds in various ways, the easiest of which is oxida-

tion, which converts the carbonÃmetal double bond into

the CÄO bond (Scheme 1).

/

Fischer carbene complexes 1 (Scheme 1) are a versatile

class of organometallic intermediates that have been

extensively used as useful stoichiometric reagents in

organic synthesis [1]. Much of the considerable current

interest concerns the application of such complexes to

/

Most of the published examples of stereoselective

reactions involving chromium carbene complexes con-

cern the case in which R²ꢀ

/

H, and include highly

stereoselective Michael additions to nitroalkenes [2],

enones [3] and aldol reactions [4]. When R²ꢀ

alkyl, the

stereoselections depend on the nature of X in the

complex: alkoxy carbenes (XꢀO) have shown variable,

stereoselective carbonÃ

/

carbon bond formation because

/

of their particular steric and electronic characteristics,

and easy conversion into a very large number of

different organic compounds. Moreover, alkylcarbene

complexes readily undergo a-deprotonation to give

enolate-type carbene complex anions, which have been

exploited in a number of stereoselective reactions. They

can be subsequently transformed into organic com-

/

but in many cases high stereoselectivity in aldol reac-

tions [5], Michael additions [6] and alkylations with

alkyl halides [6c,7]. On the contrary, in the case of

amino carbenes (XꢀN), there are only two references in

/

the literature: one concerning alkylation [8] (but the d.e.

products and related configuration are not indicated)

and the other the aldol reaction [9] (in which the aldol

addition product was obtained in poor yield and with-

out any diastereoselection).

* Corresponding author. Tel.: ꢁ

14139.

/

39-02-503-14143; fax: ꢁ39-02-503-

/

E-mail address: emanuela.licandro@unimi.it (E. Licandro).

doi:10.1016/S0022-328X(03)00523-0

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

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188

171

Scheme 2.

Scheme 1.

alkyl groups in high-yield, in this position, thus gen-

erating a new stereogenic centre [12]. Furthermore, the

rigid structure of tetracarbonyl hydrazinocarbene com-

plexes may be useful for achieving a high degree of

stereoselective control and then easily converted into the

corresponding hydrazides by means of oxidation [13].

One of the main purposes of this research was to study

diastereofacial selectivity in Michael and aldol additions

of the a-anion of hydrazinocarbene complex 6. We also

succeeded in transforming the products into the corre-

sponding hydrazides by means of oxidation of the

functionalised complexes.

The differences between the alkoxy and amino com-

plexes are mainly due to the low reactivity of a-

substituted amino carbene anions towards electrophiles

[10] and unfavourable steric effects.

Over the last few years, we have studied a new class of

Fischer-type carbene complexes: the pentacarbonyl

alkyl(hydrazino)carbene (4) and the tetracarbonyl al-

kyl(hydrazino)carbene (5) (Scheme 2).

In addition to setting up two complementary methods

of synthesis [11], we have exploited these new complexes

in the formation of a new carbonÃ

/

carbon bond by

means of the generation of the anion in the a-position

and reactions with alkyl halides, aldehydes and epoxides

[12]. These preliminary studies clearly showed that

especially tetracarbonyl hydrazinocarbene complexes 5

2. Results and discussion

have considerable synthetic potential in carbonÃ

/carbon

2.1. Michael addition

bond-forming reactions. In particular, as a result of

decreased conformational freedom and easier accessi-

bility to the a-carbon atom in chelate complexes 5

(Scheme 2), it was possible to introduce two different

Complex 6, prepared as previously described by us

[12], was transformed into the corresponding anion by

means of deprotonation in dry THF at ꢃ78 8C using n-

/

Table 1

c

^aStructures of the major products (9aꢂ

/

9d) are shown. ^bd.e. of the crude reaction products (from ¹H-NMR). d.e. after purification by column

chromatography (from weights of separated diastereoisomers in entries 2ꢂ/4 and from the unseparated mixture in entry 1).

172

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

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effect of some variables on the reaction products), we

changed some reaction parameters such as the tempera-

ture (ꢃ30 8C) or adding 1,3-dimethyl-3,4,5,6-tetrahy-

/

dro-2(1H)-pyrimidinone (DMPU) which can split the

lithium cation from the anion of complex 6 (see Section

4 for more details). In addition to 2-cyclohexen-1-one

(7b; Table 1, entry 2) and with the reaction running at ꢃ

30 8C, d.e. decreased to 75%, and the same reaction run

at ꢃ78 8C with two and four equivalents of DMPU

/

gave d.e. values of, respectively, 76 and 22%. These two

experiments show that the coordination of lithium ion

can play an important role in diastereoselectivity. In the

reaction with trans-1,3-diphenyl-propenone (7c; Table

1, entry 3), stereoselectivity was less influenced by the

temperature, and it was necessary to use DMPU as a co-

solvent in order to decrease the d.e.. However, in this

last case, the chemical yield was very low (25%) and

about half of the starting complex 6 was recovered from

the reaction mixture. The relative configurations of the

two stereocentres in complexes 9b and 9c were deter-

mined by X-ray diffraction methods. Using the spectro-

scopic data of 9b, the stereochemistry of the complexes

of entries 1 and 4 (Table 1) was assigned on the basis of

their ¹³C-NMR, and showed the characteristic differ-

ence in the chemical shift of the CrCCHCH₃in the two

diastereoisomers. A similar shift has been reported for

diastereoisomeric amides [18].

Fig. 1. View of the molecular structure of 9b together with the atomic

numbering system. Thermal ellipsoids are drawn at 30% probability

level.

BuLi, and then allowed to react with enones 7aꢂ7d at

/

the same temperature (Scheme 4). The reactions were

quenched with saturated NH₄Cl after 3 h, and the

products were the diastereoisomeric ketocomplexes 8aꢂ

/

8c and 9aꢂ9d (Scheme 4). The results of these additions

/

are summarised in Table 1. The d.e. were determined by

¹H-NMR of the crude products and, with the exception

of the reaction with the cyclopentenone (Table 1, entry

1), were very high; in the case of enone 7d, diastereos-

electivity was complete (Table 1, entry 4).

The two diastereoisomers 8 and 9 can be easily

separated using column chromatography on silica gel

(we were unable to separate the two diastereoisomers in

the case of 8a and 9a despite we have tried several

eluents) and isolated as very stable compounds; the

yields were high (except in the case of entry 3) and the

d.e. changed little (in favour of the major diastereoi-

somer) after chromatographic purification. In order to

obtain a larger amount of the minor diastereoisomers

(8b and 8c) for analytical purposes (and to study the

Views of the molecular structures of complexes 9b and

9c are given in Figs. 1 and 2, respectively.

Scheme 3. ¹H-NMR in THF-D₈.

Fig. 2. View of the molecular structure of molecule A and molecule B of complex 9c together with the atomic numbering system. Thermal ellipsoids

are drawn at 30% probability level.

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

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188

173

Scheme 4. Michael addition of carbene 6 to enones 7aꢂ

/7d.

Table 2

Table 3

˚

Selected bond lengths (A) and angles (8) for 9b

Selected bond lengths (A) and angles (8) for 9c molecules A and B (in

parentheses)

Bond distances

C(5)Ã

N(1)Ã

C(5)Ã

C(14)Ã

/

Cr(1)

2.031(4)

2.208(4)

1.458(5)

1.309(6)

1.507(6)

1.474(6)

Bond distances

/

Cr(1)

N(2)

C(6)

Cr(1)Ã

/

N(1)

2.208(5) (2.216(5))

2.044(5) (2.043(6))

1.463(6) (1.461(5))

1.324(6) (1.310(6))

1.500(7) (1.488(6))

1.223(6) (1.232(6))

1.507(7) (1.502(7))

1.552(7) (1.537(7))

1.509(7) (1.511(7))

/

Cr(1)Ã/C(5)

/

N(1)Ã

N(2)Ã

O(5)Ã

C(5)Ã

C(6)Ã

/

N(2)

/

/C(5)

/N(2)

/C(10)

/

C(19)

Bond angles

N(2)ÃC(5)Ã

C(6)ÃC(5)Ã

C(5)ÃC(6)Ã

N(2)Ã

C(5)ÃN(2)Ã

C(5)ÃCr(1)Ã

/C(6)

/

C(6)

120.0(4)

101.0(3)

139.0(3)

108.4(4)

114.8(4)

88.6(2)

/C(7)

/

/Cr(1)

C(10)Ã

Bond angles

C(5)ÃCr(1)Ã

N(2)ÃN(1)ÃCr(1)

C(5)ÃN(2)Ã

N(2)ÃC(5)Ã

C(6)ÃC(5)Ã

N(2)ÃC(10)Ã

/

C(11)

/

/Cr(1)

/

/C(7)

/

C(14)Ã

N(1)ÃCr(1)

N(1)

/

C(15)

/

/N(1)

63.7(2) (62.9(2))

88.9(3) (88.9(3))

/

107.1(3)

63.23(16)

/

N(1)

C(6)

Cr(1)

107.4(4) (106.9(4))

118.3(5) (118.5(5))

100.1(3) (101.1(4))

140.5(4) (140.0(4))

114.1(4) (115.6(4))

/

/Cr(1)

/

/C(11)

In the crystals of 9c, two crystallographically inde-

pendent complexes (conformers) are present (molecules

A and B, respectively), differing for the disposition of

the benzyl group with respect to the phenyl ring (on the

same side, molecule A, on opposite side, molecule B,

Fig. 2). Being the structures of 9b and 9c centrosymme-

trical, both enantiomers are present in the crystals, with

the stereogenic centres C6 and C8 in 9b and C6 and C17

in 9c R*,R*. Selected bond distances and angles in 9b

and 9c are given in Tables 2 and 3, respectively.

from the less hindered side of the complex, far away

from the nitrogen substituents; the low d.e. observed in

the reaction with the cyclopentenone 7a can be ex-

plained by the difficulty of the five-membered enone to

reach a transition state such as pattern 1 because, in this

case, the carbonyl group is further from the lithium ion

coordinated to chromium (Chart 1).

Compounds 9b and 9c show octahedral geometry

around the Cr atom with the hydrazinocarbene ligand

acting as chelating ligand through the N1 and C5 atoms.

˚

C5 bond distances (2.031(4) A in 9b, 2.044(5)

The Cr1Ã

/

˚

and 2.043(6) A for A and B in 9c) are comparable to

˚

those found in 6 (2.028(4) A [11b]), the first structurally

characterised hydrazinocarbene complex [11b]. Also the

˚

N1 bond distances (2.208(4) A) in 9b and 2.208(5)

Cr1Ã

/

Chart 1.

˚

and 2.216(5) A for A and B in 9c are strictly comparable

to that observed in the starting compound 6 (2.211(4)

˚

A).

2.2. Nature of carbene complex enolates

To explain the observed diastereoselectivity, we

propose two transition state models (1 and 2; Chart

1); the lithium ion can bring together the two reacting

molecules (enone and complex anion) in a tidy transition

state that leads to a high level of diastereoselectivity. A

similar lithium interaction has been proposed for the

Michael addition of ester enolates with unsaturated

esters [19]. In models 1 and 2, the enone’s approach is

Models 1 and 2 imply a precise configuration of the

carbene enolate, which we therefore tried to clarify.

Although Fischer-type carbene complex enolates are

widely used in stereoselective reactions, there are few

published studies of the nature of lithium enolates

(which are most frequently used). X-ray structure of a

potassium 18-crown-6 alkoxy carbene complex enolate

174

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

Scheme 5.

Table 4

^aStructures of the major products (11aꢂ

/

11e) are shown. ^bUnless otherwise specified, the anion concentration was about 0.07 M. ^cd.e. of the crude

reaction products (by NMR). ^dd.e. after purification (from the weights of the separated diastereoisomers). Major product is the anti-isomer (12c).

e

^fYields of the Michael addition products are in brackets.

has been reported [14], but the naked solid-state anion is

not comparable with lithium salt in THF solution

because of different natures of the two cations and the

effect of the solvent. Furthermore, the NMR and IR

spectra of the lithium and PPN [bis(triphenylphosphor-

anylidene)ammonium]alkoxy carbene complex enolate

[15] in THF solution are identical and there are no

isocarbonyl bands [16] in IR spectra, thus excluding any

interaction between the cation and carbonyls of the

complex [17]. It is plausible that lithium is separated

from the anion in solution [15] and it may play an

important role as a Lewis acid in improving the

reactivity to electrophiles such as enones and aldehydes;

we have observed a considerable decrease in reactivity in

aldol and Michael additions when compounds capable

of binding the lithium ion were added (Table 1, entries 2

and 3; Table 4, entry 3). We therefore decided to study

the enolate of 6 by means of NMR. In THF-D₈

solution, an NOE experiment (Scheme 3) showed that

the enolate of 6 has a Z configuration, that is the same

as that expected for the corresponding amide enolate.

The anion was generated with n-BuLi at ꢃ78 8C and

/

with a concentration analogous to the one used in the

reactions. The anion of 6 is also very stable (under

nitrogen atmosphere) at room temperature. The NMR

spectrum does not change between ꢃ78 and 20 8C, and

/

even in the presence of a small excess of complex 6, no

isomerisation was observed. The ¹H- and ¹³C-NMR

spectra (see Section 4 for more details) indicate that the

enolate structure is best described as a vinyltetracarbo-

nylchromium anion in which the negative charge is

delocalised on the organometallic group (Scheme 3), a

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

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175

Table 5

˚

Selected bond lengths (A) and angles (8) for 11e (left) and 12e (right)

Bond distances

Cr(1)Ã

/

N(1)

2.206(10)

2.019(11)

1.438(12)

1.331(13)

1.490(12)

1.503(15)

1.530(13)

2.206(3)

2.051(3)

1.461(4)

1.304(4)

1.483(4)

1.502(4)

1.530(5)

/C(5)

N(1)Ã

N(2)Ã

C(5)Ã

C(8)Ã

/

N(2)

/C(5)

/C(11)

/C(8)

/C(9)

Bond angles

C(5)ÃCr(1)Ã

N(2)ÃN(1)ÃCr(1)

C(5)ÃN(2)Ã

N(2)ÃC(5)Ã

C(8)ÃC(5)Ã

/

N(1)

62.8(4)

89.9(7)

62.70(11)

89.42(16)

106.6(2)

120.5(3)

101.1(2)

137.6(2)

/

N(1)

C(8)

Cr(1)

105.7(10)

118.1(10)

101.5(8)

140.1(9)

/

Cr(1)

The best results were obtained by running the

reactions at ꢃ78 8C for 30 min: we isolated a mixture

Fig. 3. View of the molecular structure of 11e together with the atomic

numbering system. Thermal ellipsoids are drown at 30% probability

level.

/

of the two diastereoisomers 11 and 12 with very high

yields and d.e. (except for aldehyde 10b, Table 4, entry

2). The d.e. values were inferred from the ¹H-NMR

spectra of the crude reaction mixtures. The two diaster-

eoisomers 11 and 12 could be easily separated by

column chromatography over silica gel. All the aldol

adducts 11 and 12 were very stable and the d.e. values

did not change after the purification step. The only

exception was entry 4, in which the minor diastereoi-

somer 12d is poorly stable on silica gel. At ꢃ78 8C, the

/

reactions were not reversible and the d.e. values did not

change even after longer reaction times (from 30 min to

3.5 h); entry 5 was an exception, probably because the

electron-rich ferrocenyl moiety may favour a retro-aldol

reaction and thus enrich the reaction mixture of the

more thermodynamically stable anti-isomer 12e.

The relative configurations at the two stereocentres of

complexes 11e and 12e were determined by X-ray

diffraction methods. Views of the molecular structures

of the two isomeric complexes 11e (syn) and 12e (anti)

are given in Fig. 3 and 4, respectively.

Fig. 4. View of the molecular structure of 12e together with the atomic

numbering system. Thermal ellipsoids are drown at 30% probability

level.

Lists of the selected bond distances and angles in the

isomers are given in Table 5.

structure that fits the diastereoselection models dis-

cussed above.

Being the structures of 11e and 12e centrosymme-

trical, both enantiomers are present in the crystals, with

the stereogenic centres C8 and C10 R*,S* in 11e and

R*,R* in 12e. Both isomers show octahedral geometry

around the Cr atom with the hydrazinocarbene ligand

acting as chelating ligand through the N1 and C5 atoms.

2.3. Aldol addition

The Cr1Ã

/

C5 and Cr1Ã

/

N1 bond distances in the two

˚

isomers (2.019(11) and 2.206(10) A in 11e and 2.051(3)

The enolate generated from complex 6 reacted in

aldol-type addition reactions with the aldehydes 10aꢂ

/

˚

and 2.206(3) A in 12e) are in agreement with those

10e. The chosen aldehydes are representative of different

classes: aromatic (10a), linear aliphatic (10b), branched

aliphatic (10c), a, b-unsaturated (10d) and organome-

tallic-containing aldehydes (10e). Table 2 shows the d.e.

values and chemical yields of the aldol addition products

observed in 9b, 9c and 6. The orientation of the benzyl

group in syn diastereoisomer 11e is different from that

in anti diastereoisomer 12e; in the former it is disposed

on the same side of the methyl atom C9, whereas in the

latter it is pointing in the opposite side.

(11aꢂ

/

11e and 12aꢂ12e, Scheme 5).

/

176

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

Table 6

Reaction conditions: (a) Ca(OCl)₂/KH₂PO₄/K₂HPO₄/N(n-Bu)₄HSO₄; (b) NaBO₃×

/4H₂O/KH₂PO₄/I₂; (c) reference amides and N-hydroxyamide

with an identical acidic moiety of hydrazides.

The relative configuration of complexes 11aꢂ

/

11d and

12d (Table 4, entries 1-4) was assigned by ¹H-NMR

12aꢂ

/

on the basis of the characteristic coupling constant

J_CrCCHCHOH[20] (in analogy to what has been reported

for similar amino carbene complex aldols 9), and by

comparing the oxidation products of the carbene com-

plexes with the isolobal organic compounds (see Table

6).

In order to obtain a larger amount of the minor

diastereoisomers for analytical purposes, the reactions

with aldehydes 10aꢂ

/

10d were performed at ꢃ30 8C and

/

led to a significant reduction in d.e.. The d.e. values in

the aldol reaction with hydrazinocarbene complex 6

were not affected by the concentration of the enolate

(Table 4, entry 3). The lithium ion is important in order

to obtain high syn diastereoselectivity and a high

reaction rate: when an equimolar amount of Kriptofix

221 was added to the enolate carbene complex (Table 4,

entry 3), the aldol reaction was very slow (TLC clearly

showed a very low reaction rate) and there was a

diastereoselectivity inversion in favour of the anti-

Scheme 6.

diastereoisomer. The chair-like Zimmerman-Traxler

models (Chart 2) can explain the formation of the major

(syn) and minor (anti) diastereoisomers (the enolate

configuration has been discussed above). Model B is less

favoured than A because of the dominant steric inter-

action between the enolate N-benzyl group and the

aldehyde axial substituent (Chart 2).

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

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188

177

3. Conclusions

The anion generated from the tetracarbonyl hydrazi-

nocarbene complex 6 easily adds to enones and alde-

hydes to give the corresponding 1,4 and aldol addition

products in high chemical yields and diastereoselectivity.

The major diastereoisomer obtained from the Michael

additions was anti, as determined by the X-ray analysis

of adducts 9b and 9c. The stereochemical outcome of

these reactions can be explained by considering the

transition state models 1 and 2. Enolisation of hydra-

zinocarbene 6 leads to the formation of the Z enolate, as

inferred from one-dimensional NOE experiments of the

anion.

Chart 2.

2.4. Oxidations

Oxidation of the metalÃ

/

carbon double bond to a

carbonyl group in Fischer-type carbene complexes is still

the easiest and most convenient method of recovering

the organic ligand as a stable organic molecule. This

transformation is generally highly efficient provided that

the appropriate oxidation protocol is chosen. A very

large number of different oxidation reagents and condi-

tions have so far been published because each class of

chromium carbene complexes (alkoxy, amino, hydrazi-

no) often requires its own oxidant. Furthermore, if

oxidation-sensitive substituents are present in the car-

bene complex structure (hydroxy group, amino group,

etc.), it is necessary to select the right reaction conditions

in order to prevent undesirable reactions.

During our studies of the reactivity of the penta- and

tetracarbonyl hydrazinocarbene complexes 4 and 5, we

set up the best conditions for transforming hydrazino-

carbenes into organic isolobal hydrazides [13].

In this study, we used these protocols to transform

some of the Michael and aldol adducts into the

corresponding organic hydrazides. In particular, com-

The major diastereoisomer obtained in the addition of

6 to aldehydes 10aꢂ10e was the syn, as inferred from the

/

X-ray analysis of a single crystal of adducts 11e and 12e.

The stereochemical outcome of the aldol additions can

be explained by considering the classical Zimmerman-

Traxler transition state model.

Some of the new hydrazinocarbene complexes ob-

tained from the Michael and aldol additions were

submitted to oxidation, which led to the formation of

the corresponding hydrazides in very high chemical

yields, without any racemisation. These diastereoiso-

meric hydrazides have not been previously reported in

the literature. We have thus demonstrated the usefulness

of tetracarbonyl hydrazinocarbene complex 6 in the

stereoselective formation of new carbonÃ

/

carbon bonds,

which can be attributed to the particular steric and

electronic characteristics of this very stable complex.

plexes 9b, 9c, 11bꢂ11e, 12b and 12c were oxidised using

/

4. Experimental

two different methods: (i) in the first, the oxidant KOCl,

generated in situ from Ca(OCl)₂and the phosphate

buffer K₂HPO₄/KH₂PO₄under phase-transfer condi-

tions (Scheme 6), was used to transform 9b and 9c into

13b and 13c (see Section 4); (ii) in the second, the

oxidant iodine was generated in situ by means of the

oxidation of KI with sodium perborate in the presence

4.1. General experimental considerations

All the reactions on carbene enolates were carried out

under an atmosphere of dry argon or nitrogen; the

glassware was flame-dried before use. THF was dried by

means of distillation over sodium wires/benzophenone

before use; the butyllithium solutions were titrated

before use. The Ca(OCl)₂(Fluka-RdH) was technical

(about 65%). Flash and vacuum chromatography were

of KH₂PO₄(Scheme 6), and gave complexes 14bꢂ

and 15b and 15c.

In all cases, the d-keto (Table 3, 13b and 13c, entries 1

and 2) and b-hydroxyhydrazides (Table 6, entries 3ꢂ8,

14bꢂ14e and 15b and 15c) were obtained in very high

/14e

/

performed using Merck silica gel 60, 230ꢂ400 mesh. The

melting points were determined using a Buchi 510

¨

/

chemical yields as pure diastereoisomers without any

epimerisation during the oxidation reactions.

The new hydrazides were fully characterised, with the

¹H- and ¹³C-NMR chemical shifts and coupling con-

stants being used to confirm the stereochemistry of the

diastereoisomers. The spectroscopic data of hydrazides

apparatus and are uncorrected. The diastereoselectivity

of the reactions was determined by NMR of the crude

products, except in the case of the synthesis of com-

plexes 8ꢂ9c in the presence of DMPU as co-solvent, in

/

which the crude products were prepurified (in order to

remove the DMPU) by means of very fast vacuum

chromatography with a short column (eluent: CH₂Cl₂).

13b, 13c, 14bꢂ14e, 15b and 15c were in good agreement

/

1

The H-NMR (300 MHz, CDCl₃) and ¹³C-NMR (75

with those of the amides and N-hydroxyamides derived

from the same carboxylic acids present in the hydrazide

structure.

MHz, CDCl₃) spectra were recorded using a Bruker AC

300 and Bruker AMX 300. The IR spectra were

178

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

recorded using a Perkinꢂ

spectra (EI, FAB) were recorded using a Vg Analytical

7070 EQ.

/

Elmer FT-IR 1725X. The mass

300 MHz) d (ppm): 7.5ꢂ

d, Jꢀ17.1 Hz, CH₂Ph maj. diast.), 4.75 (1H, d, Jꢀ

Hz, CH₂Ph min. diast.), 4.64 (1H, d, Jꢀ17.1 Hz,

CH₂Ph maj. diast.), 4.60 (1H, d, Jꢀ17.0 Hz, CH₂Ph

/

7.1 (5H, m, H_aromat), 4.79 (1H,

/

/17.0

/

4.2. Anion of (Z)-tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)ethylcarbene]chromium(0) (6)

min. diast.), 2.89 (3H, s, NMe₂maj. diast.), 2.87 (3H, s,

NMe₂min. diast.), 2.81 (3H, s, NMe₂maj. diast.), 2.79

(3H, s, NMe₂min. diast.), 2.7ꢂ

CHCH₂COCH₂), 1.9ꢂ1.5 (2H, m, CH₂CH₂CO), 1.41

(3H, d, Jꢀ4.8 Hz, CrCCHCH₃min. diast.), 1.34 (3H, d,

Jꢀ

6.5 Hz, CrCCHCH₃maj. diast.); ¹³C-NMR DEPT

(CDCl₃, 75 MHz) d (ppm): 294.7 (C_carbene), 231.9,

229.4, 219.4, 219.2, 218.3, 217.8, 217.2 (CO complexꢁ

/

2.2 (6H, m, CrCCHꢁ

/

¹H-NMR (THF-D₈, 300 MHz) d (ppm): 7.5ꢂ

m, H_arom.), 4.56 (1H, q, Jꢀ5.9 Hz, CH), 3.82 (2H, s,

/6.9 (5H,

/

CH₂Ph), 2.59 (6H, s, NMe₂), 1.52 (3H, d, Jꢀ

/

5.9 Hz,

CHCH₃); ¹³C-NMR DEPT (THF-D₈, 75 MHz) d

(ppm): 240.4, 232.0, 225.6 (CO), 175.8 (C_carbene), 142.9

/

(C_qPh), 128.3, 127.7, 126.1 (C Ph), 93.8 (CÄ

/

CH), 51.4

CO ketone), 133.5 (Cq Ph), 129.6, 128.7, 126.1 (C Ph),

52.7, 52.3 (NMe₂), 49.4 (CH₂Ph), 49.1 (CrCCH), 44.2

(CHCH₂CO min. diast.), 43.0 (CrCCHCH maj. diast.),

42.6 (CHCH₂CO maj. diast.), 42.3 (CrCCHCH min.

diast.), 38.7 (CH₂CH₂CO maj. diast.), 37.9

(CH₂CH₂CO min. diast.), 29.0 (CH₂CH₂CO maj.

diast.), 27.0 (CH₂CH₂CO min. diast.), 18.3 (CH₃maj.

diast.), 17.2 (CH₃min. diast.); IR/FT (neat) n (cm^ꢃ1):

1998 (trans-CO), 1868, 1833 (cis-CO), 1739 (CO ke-

tone), 737 (gCH_arom.), 698 (dCH_arom.).

(NMe₂), 49.7 (CH₂Ph), 18.4 (CHCH₃).

4.3. Michael addition

4.3.1. Michael addition of the enolate of the

tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)ethylcarbene]chromium(0) (6) with

enones: general procedure

n-BuLi (solution in hexane, one equivalent) was

added dropwise to a ꢃ78 8C solution of complex 6

/

(one equivalent) in dry THF (5 ml for 0.3 mmol of

complex 6), and the mixture was allowed to react at the

same temperature for 30 min. Where stated, after 20 min

4.3.3. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(1-methyl)methylene-(3-

cyclohexanone)carbene]chromium(0) (8b and 9b)

at ꢃ

/

78 8C, the mixture was warmed to ꢃ

/

30 8C for 10

Reaction at ꢃ78 8C. Complex 6: 103 mg (0.29 mmol,

/

min before adding the enone; in some reactions, two or

four equivalents of DMPU were added after anion

one equivalent); dry THF: 5 ml; n-BuLi, 1.55 M: 0.195

ml (0.30 mmol, 1.02 equivalents); 2-cyclohexen-1-one

7b: 0.035 ml (0.36 mmol, 1.2 equivalents). Crude

product: 146.5 mg; d.e.: 92%. After purification (eluent:

formation at ꢃ

added and, after stirring for 3 h at ꢃ

min for the reactions at ꢃ30 8C), 0.25 ml of water was

/

78 8C. Enone (1.2 equivalents) was

/

78 8C (1 h 30

/

Et₂O/AcOEtꢀ9/1), 7 mg of complex 8b and 102 mg of

/

added at the same temperature. The organic solvent was

removed in vacuo and the residue dissolved with CH₂Cl₂

and dried over Na₂SO₄. The solvent was then evapo-

rated at reduced pressure, giving a crude red oil which

was purified by flash chromatography over silica gel (15

g).

complex 9b were obtained; d.e. after purification: 87%;

yield: 81.7%.

Reaction at ꢃ30 8C. Complex 6: 103 mg (0.29 mmol,

/

one equivalent); dry THF: 5 ml; n-BuLi, 1.35 M: 0.22 ml

(0.3 mmol, 1.01 equivalents); 2-cyclohexen-1-one 7b:

0.03 ml (0.31 mmol, 1.06 equivalents). Crude product:

123 mg; d.e.: 75%. After purification (eluent: Et₂O/

4.3.2. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(1-methyl)methylene-(3-

AcOEtꢀ9/1), 12 mg of complex 8b and 69 mg of

complex 9b were obtained; d.e. after purification: 70%;

yield: 52.0%.

/

cyclopentanone)carbene]chromium(0) (8ꢂ

/

9a): reaction

at ꢃ78 8C

/

Reaction at ꢃ78 8C in the presence of two equivalents

/

Complex 6: 103 mg (0.29 mmol, one equivalent); dry

THF: 5 ml; n-BuLi, 1.43 M: 0.21 ml (0.30 mmol, 1.03

equivalents); cyclopentenone 7a: 0.03 ml (0.37 mmol,

1.27 equivalents). Crude product: 153.5 mg; d.e.: 42%.

After purification (eluent: Et₂O), 0.111 g of complex 1

was obtained as a mixture of diastereoisomers; d.e. after

purification: 47%; yield: 87.1%.

of DMPU. Complex 6: 108 mg (0.31 mmol, one

equivalent); dry THF: 5 ml; n-BuLi, 1.32 M: 0.24 ml

(0.32 mmol, 1.03 equivalents); after 30 min, 0.075 ml of

DMPU (0.62 mmol, 2.03 equivalents) was added; after

15 min, 0.035 ml of 2-cyclohexen-1-one 7b (0.36 mmol,

1.18 equivalents) was added. Crude product: 232 mg;

d.e.: 76%. After purification (eluent: Et₂O/AcOEtꢀ9/

/

1), 10 mg of the complex 8b and 109 mg of complex 9b

were obtained; d.e. after purification: 83%; yield: 86.3%.

4.3.2.1. (R*,R*) and (R*,S*)-Tetracarbonyl[(N-

benzyl-N?,N?-dimethylhydrazinyl)-(1-methyl)methylene-

Reaction at ꢃ78 8C in the presence of four equivalents

/

(3-cyclopentanone)carbene]chromium(0) (8ꢂ

plexes 8a and 9a (mixture of diastereoisomers): red

1

viscous oil; Rf: 0.14 (eluent: Et₂O). H-NMR (CDCl₃,

/

9a). Com-

of DMPU. Complex 6: 103 mg (0.29 mmol, one

equivalent); dry THF: 5 ml; n-BuLi, 1.55 M: 0.195 ml

(0.30 mmol, 1.02 equivalents); after 30 min, 0.145 ml of

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

/

188

179

DMPU (1.2 mmol, 4.08 equivalents) was added; after 15

min, 0.035 ml of 2-cyclohexen-1-one 7b (0.36 mmol, 1.23

equivalents) was added. Crude product: 301 mg; d.e.:

4.3.4. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(2,4-diphenyl-1-methyl-4-

oxo)butylcarbene]chromium(0) (8c and 9c)

22%. After purification (eluent: Et₂O/AcOEtꢀ

/9/1), 35

Reaction at ꢃ78 8C. Complex 6: 103 mg (0.29 mmol,

/

mg of complex 8b and 62 mg of complex 9b were

obtained; d.e. after purification: 27%; yield: 73.0%.

one equivalent); dry THF: 5 ml; n-BuLi, 1.55 M: 0.19 ml

(0.29 mmol, 1.02 equivalents); 1,3-diphenyl-propenone

7c: 73 mg (0.35 mmol, 1.21 equivalents). Crude product:

184.5 mg; d.e.: 98%. After purification (eluent: Et₂O/

4.3.3.1. (R*,S*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(1-methyl)methylene-(3-

AcOEtꢀ

after purification ꢀ

Reaction at ꢃ78 8C in the presence of four equivalents

of DMPU. Complex 6: 103 mg (0.29 mmol, one

equivalent); dry THF: 2 ml; n-BuLi, 1.55 M: 0.195 ml

(0.30 mmol, 1.03 equivalents); after 30 min, 0.145 ml of

DMPU (1.2 mmol, 4.12 equivalents) was added; after 15

min, 72 mg of 1,3-diphenyl-propenone 7c (0.35 mmol,

1.19 equivalents) was added. Crude product: 327 mg;

d.e. after prepurification: 89%. After purification (elu-

/

9/1), 96.5 mg of complex 9c was obtained; d.e.

/98%; yield: 59.6%.

cyclohexanone)carbene]chromium(0) (8b). Complex 8b

(minor diastereoisomer): orange solid; m.p. 139 8C

(Et₂O/pentane); Rf: 0.23 (eluent: Et₂O/AcOEtꢀ9/1).

Anal. Calcd for C₂₂H₂₆CrN₂O₅: C, 58.66; H, 5.82; N,

6.22. Found: C, 58.33; H, 5.60; N, 6.52%. ¹H-NMR

/

(CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

4.82 (1H, d, Jꢀ17.0 Hz, CH₂Ph), 4.47 (1H, d, Jꢀ

Hz, CH₂Ph), 2.90 (3H, s, NMe₂), 2.71 (3H, s, NMe₂),

2.75ꢂ1.70 (9H, m, CrCCHꢁcycloesanone), 1.18 (3H, d,

Jꢀ

6.3 Hz, CrCCHCH₃); ¹³C-NMR DEPT (CDCl₃, 75

/7.1 (5H, m, H_aromat),

/

17.0

/

ent: Et₂O/ETPꢀ7/3), 5 mg of complex 8c and 93 mg of

/

complex 9c were obtained; d.e. after purification: 90%;

yield: 59.5%.

MHz) d (ppm): 295.2 (C_carbene), 231.8, 229.4, 218.9,

218.5 (CO), 211.5 (CO ketone), 133.9 (Cq Ph), 129.4,

128.5, 126.2 (C Ph), 52.8, 52.1 (NMe₂), 49.8 (CH₂Ph),

46.9 (CHCH₂CO), 44.8 (CrCCH), 43.1 (CrCCHCH),

41.5 (CH₂CH₂CO), 26.6 (CH₂CH₂CO), 23.5

(CHCH₂CH₂), 16.8 (CH₃). IR/FT (neat) n (cm^ꢃ1):

1997 (trans-CO), 1868, 1829 (cis-CO), 1709 (CO ke-

tone), 728 (gCH_arom.), 682 (dCH_arom.). MS (FAB^ꢁ), m/

Reaction at ꢃ78 8C in DMPU as co-solvent. Complex

/

6: 103 mg (0.29 mmol, one equivalent); dry THF: 5 ml;

n-BuLi, 1.55 M: 0.19 ml (0.29 mmol, 1.02 equivalents);

after 30 min, 3 ml of DMPU (24.9 mmol, 86.4

equivalents) were added; after 15 min, 0.0731 of 1,3-

diphenyl-propenone 7c (0.35 mmol, 1.22 equivalents)

were added. d.e. after prepurification: 74%. After

z 450 [M^ꢁ], 422 [M^ꢁÃ

4CO], 293 [M^ꢁÃ

4COÃ

PhCH₂], 91 [C₇H₇^ꢁ].

/

CO], 366 [M^ꢁÃ

/

3CO], 338 [M^ꢁÃ

4COÃ

/

purification (eluent: Et₂O/ETPꢀ7/3), 54 mg of complex

/

HNMe₂], 247 [M^ꢁÃ

/

6 (yield of recovery: 53.1%), 5 mg of complex 8c and 35

mg of complex 9c were obtained; d.e. after purification:

75%; yield: 24.7%.

Reaction at ꢃ30 8C in the presence of four equivalents

/

4.3.3.2. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(1-methyl)methylene-(3-

of DMPU. Complex 6: 103 mg (0.29 mmol, one

equivalent); dry THF: 5 ml; n-BuLi, 1.55 M: 0.19 ml

(0.29 mmol, 1.02 equivalents); after 20 min, 0.140 ml of

DMPU (1.16 mmol, four equivalents) was added; after

cyclohexanone)carbene]chromium(0) (9b). Data for

complex 9b (major diastereoisomer): orange solid; m.p.

129 8C (CH₂Cl₂/pentane); Rf: 0.18 (eluent: Et₂O/

10 min, at ꢃ30 8C 72 mg of 1,3-diphenyl-propenone 7c

/

AcOEtꢀ

/

9/1). Anal. Calcd for C₂₂H₂₆CrN₂O₅: C,

58.66; H, 5.82; N, 6.22. Found: C, 58.82; H, 5.70; N,

(0.34 mmol, 1.19 equivalents) was added; d.e. after

prepurification: 90%. After purification (eluent: Et₂O/

1

6.09%. H-NMR (CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

(5H, m, H_aromat), 4.76 (1H, d, Jꢀ17.0 Hz, CH₂Ph), 4.55

(1H, d, Jꢀ17.0 Hz, CH₂Ph), 2.84 (3H, s, NMe₂), 2.72

(3H, s, NMe₂), 2.7ꢂ2.6 (1H, m, CrCCH), 2.45ꢂ1.6 (9H,

m, cycloesanone), 1.23 (3H, d, Jꢀ6 Hz, CrCCHCH₃);

/

7.1

ETPꢀ7/3), 6 mg of complex 8c and 94 mg of complex

/

9c were obtained; d.e. after purification: 88%; yield:

61.8%.

/

4.3.4.1. (R*,S*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(2,4-diphenyl-1-methyl-4-

¹³C-NMR DEPT (CDCl₃, 75 MHz) d (ppm): 295.6

(C_carbene), 232.0, 229.9, 219.7, 218.9 (CO), 210.5 (CO

ketone), 133.9 (Cq Ph), 130.0, 129.2, 126.6 (C Ph), 52.6,

52.1 (NMe₂), 49.9 (CH₂Ph), 49.2 (CrCCH), 45.3

(CHCH₂CO), 44.0 (CrCCHCH), 41.8 (CH₂CH₂CO),

31.5 (CH₂CH₂CO), 24.9 (CHCH₂CH₂), 17.3 (CH₃). IR/

FT (neat) n (cm^ꢃ1): 1996 (trans-CO), 1844 (cis-CO),

1708 (CO ketone), 736 (gCH_arom.), 686 (dCH_arom.). MS

oxo)butylcarbene]chromium(0) (8c). Complex 8c

(minor diastereoisomer): orange solid; m.p. 141 8C

(CH₂Cl₂/pentane); Rf: 0.17 (eluent: ETP/AcOEtꢀ4/6).

/

Anal. Calcd for C₃₁H₃₀CrN₂O₅: C, 66.18; H, 5.37; N,

4.98. Found: C, 65.92; H, 5.53; N, 4.72%. ¹H-NMR

(CDCl₃, 300 MHz) d (ppm): 7.9ꢂ

4.17 (1H, d, Jꢀ17.2 Hz, CH₂Ph), 4.08 (1H, d, Jꢀ

Hz, CH₂Ph), 3.9ꢂ3.75 (1H, m, CHCHPh), 3.75ꢂ

(2H, m, CH₂CO), 3.06 (1H, q, Jꢀ6.6 Hz, CH₃CH),

2.82 (3H, s, NMe₂), 2.64 (3H, s, NMe₂), 1.31 (1H, d, Jꢀ

/

7.0 (15H, m, H_aromat),

17.2

3.6

/

(FAB^ꢁ), m/z 450 [M^ꢁ], 378 [M^ꢁÃ

[M^ꢁÃ4CO], 293 [M^ꢁÃ HNMe₂], 247 [M^ꢁÃ

4COÃ

PhCH₂], 91 [C₇H₇^ꢁ].

/

COÃ

/

NMe₂], 338

/

180

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

6.5 Hz, CH₃CH); ¹³C-NMR DEPT (CDCl₃, 75 MHz) d

(ppm): 295.3 (C_carbene), 232.2, 229.7, 220.9, 218.5 (CO),

(1H, d, Jꢀ

6.5 Hz, CH₃CH); ¹³C-NMR DEPT (CDCl₃,

/

75 MHz) d (ppm): 294.0 (C_carbene), 232.5, 229.8, 220.2,

219.3 (CO), 207.3 (CO ketone), 142.9, 134.1 (Cq Ph),

129.9, 129.1, 128.9, 127.7, 126.3 (C Ph), 52.9, 52.4

(NMe₂), 49.5 (CH₂Ph), 49.0 (CrCCH), 47.2 (CH₂CO),

45.7 (CHPh), 30.6 (CH₃CO), 18.6 (CHCH₃). IR/FT

(neat) n (cm^ꢃ1): 1998 (trans-CO), 1874, 1836 (cis-CO),

1712 (CO ketone), 738 (gCH_arom.), 689 (dCH_arom.).

199.0 (CO ketone), 142.6, 137.6, 134.4 (Cq Ph), 134ꢂ125

/

(C Ph), 52.8 (NMe₂), 49.6 (CH₂Ph), 48.8 (CrCCH), 47.9

(CHPh), 40.6 (CH₂CO), 17.5 (CH₃). IR/FT (Nujol) n

(cm^ꢃ1): 1996 (trans-CO), 1892, 1841 (cis-CO), 1684

(CO ketone), 740 (gCH_arom.), 680 (dCH_arom.).

4.3.4.2. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(2,4-diphenyl-1-methyl-4-

4.4. Aldol additions

oxo)butylcarbene]chromium(0) (9c). Complex 9c (ma-

jor diastereoisomer): orange solid; m.p. 141 8C (CH₂Cl₂/

4.4.1. Aldol addition of the enolate of the

pentane); Rf: 0.24 (eluent: ETP/AcOEtꢀ

Calcd for C₃₁H₃₀CrN₂O₅: C, 66.18; H, 5.37; N, 4.98.

1

Found: C, 65.92; H, 5.53; N, 4.72%. H-NMR (CDCl₃,

/

4/6). Anal.

tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)ethylcarbene]chromium(0) (6) with

aldehydes: general procedure

300 MHz) d (ppm): 7.85ꢂ

(1H, d, Jꢀ17.2 Hz, CH₂Ph), 3.98 (1H, d, Jꢀ

CH₂Ph), 3.84 (1H, td, J₁ꢀ10.0 Hz, J₂ꢀ

16.1 Hz, J_vic

10.0 Hz, J₂ꢀ6.5 Hz,

CH₃CH), 2.53 (3H, s, NMe₂), 2.49 (3H, s, NMe₂), 1.53

(1H, d, Jꢀ

6.5 Hz, CH₃CH); ¹³C-NMR DEPT (CDCl₃,

/

6.85 (15H, m, H_aromat), 4.21

17.2 Hz,

4.0 Hz,

4.0

10.0

The procedure was similar to that of the Michael

reactions with the following differences: about 4 ml of

dry THF per 0.3 mmol of complex 6 and two

equivalents of aldehyde were used; the reactions were

/

CHCHPh), 3.71 (1H, dd, J_gem

Hz, CH₂CO), 3.29 (1H, dd, J_gem

Hz, CH₂CO), 3.00 (1H, dq, J₁ꢀ

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

quenched after 3 h 30 min or 30 min at ꢃ

1 h at ꢃ30 8C; where stated, a more concentrated

solution of complex 6 was used; in one reaction,

Kriptofix 211 was added after anion formation at ꢃ

/

78 8C and after

/

75 MHz) d (ppm): 293.8 (C_carbene), 232.6, 229.9, 220.0,

219.5 (CO), 198.7 (CO ketone), 143.1, 137.4, 134.2 (Cq

Ph), 133.4, 129.9, 129.0, 128.9, 128.5, 127.6, 126.9, 126.4

(C Ph), 52.9, 52.4 (NMe₂), 49.6 (CH₂Ph), 49.0

(CrCCH), 45.9 (CHPh), 42.1 (CH₂CO), 18.7 (CH₃).

IR/FT (neat) n (cm^ꢃ1): 1997 (trans-CO), 1864 (cis-CO),

1685 (CO ketone), 736 (gCH_arom.), 688 (dCH_arom.).

78 8C.

4.4.2. Synthesis of the tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(ethyl-1-methyl-2-phenyl-2-

hydroxy)carbene]chromium(0) (11a and 12a)

Reaction at ꢃ78 8C for 30 min. Complex 6: 108 mg

/

(0.31 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.64 M: 0.19 ml (0.31 mmol, 1.02 equivalents); benzal-

dehyde 10a: 0.065 ml (0.64 mmol, 2.1 equivalents).

Crude product: 160 mg; d.e.: 95%. After purification

4.3.5. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(1,4-dimethyl-2-phenyl-4-

oxo)butylcarbene]chromium(0) (9d): reaction at ꢃ

78 8C

Complex 6: 103 mg (0.29 mmol, one equivalent); dry

/

(eluent: CH₂Cl₂/ETPꢀ8/2), 3 mg of complex 12a and

123.5 mg of complex 11a were obtained; d.e. after

purification: 95%; yield: 90.1%.

/

THF: 5 ml; n-BuLi, 1.503 M: 0.195 ml (0.29 mmol, 1.02

equivalents); 4-phenyl-but-3-en-2-one 7d: 51 mg (0.35

Reaction at ꢃ78 8C for 3 h 30 min. Complex 6: 108

/

mg (0.31 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.64 M: 0.19 ml (0.31 mmol, 1.02 equivalents); benzal-

dehyde 10a: 0.065 ml (0.64 mmol, 2.1 equivalents).

Crude product: 160 mg; d.e.: 95%. After purification

mmol, 1.22 equivalents). Crude product: 185 mg; d.e. ꢀ

98%. After purification (eluent: Et₂O/AcOEtꢀ9/1), 125

mg of complex 9d was obtained; d.e. after purification

98%; yield: 86.7%.

/

ꢀ

/

(eluent: CH₂Cl₂/ETPꢀ8/2), 3 mg of complex 12a and

/

116 mg of complex 11a were obtained; d.e. after

purification: 95%; yield: 84.8%.

4.3.5.1. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-(1,4-dimethyl-2-phenyl-4-

Reaction at ꢃ30 8C. Complex 6: 108 mg (0.31 mmol,

/

oxo)butylcarbene]chromium(0) (9d). Complex 9d: or-

ange solid; m.p. 119 8C (Et₂O/pentane). Anal. Calcd for

C₂₆H₂₈CrN₂O₅: C, 62.39; H, 5.64; N, 5.60. Found: C,

one equivalent); dry THF: 4 ml; n-BuLi, 1.64 M: 0.19 ml

(0.31 mmol, one equivalent); benzaldehyde 10a: 0.065 ml

(0.64 mmol, 2.1 equivalents). Crude product: 150 mg;

1

62.25; H, 5.50; N, 5.71%. H-NMR (CDCl₃, 300 MHz)

d.e.: 25%. After purification (eluent: CH₂Cl₂/ETPꢀ8/

/

d (ppm): 7.4ꢂ

17.2 Hz, CH₂Ph), 4.02 (1H, d, Jꢀ

3.70 (1H, td, J₁ꢀ10.0 Hz, J₂ꢀ4.4 Hz, CHCHPh), 3.13

(1H, dd, J_gem15.8 Hz, J_vic4.4 Hz, CH₂CO), 2.93

(1H, dq, J₁ꢀ10.0 Hz, J₂ꢀ6.5 Hz, CH₃CH), 2.83 (1H,

dd, J_gem15.8 Hz, J_vic10.0 Hz, CH₂CO), 2.59 (3H, s,

NMe₂), 2.55 (3H, s, NMe₂), 2.04 (3H, s, CH₃CO), 1.49

/

6.9 (10H, m, H_aromat), 4.20 (1H, d, Jꢀ

/

2), 39 mg of complex 12a and 64 mg of complex 11a

were obtained; d.e. after purification: 24%; yield: 71.7%.

/17.2 Hz, CH₂Ph),

/

ꢀ

/

ꢀ

/

4.4.2.1. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(ethyl-1-methyl-2-phenyl-2-

hydroxy)carbene]chromium(0) (11a). Complex 11a

(major diastereoisomer): red viscous oil; Rf: 0.2 (eluent:

/

ꢀ

/

ꢀ

/

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

/

188

181

ETP/CH₂Cl₂ꢀ

(ppm): 7.5ꢂ6.9 (10H, m, H_aromat), 5.08 (1H, dd, J₁ꢀ

Hz, J₂ꢀ2.2 Hz, OHCHPh), 4.19 (2H, s, CH₂Ph), 2.99

(1H, dq, J₁ꢀ8 Hz, J₂ꢀ6.2 Hz, CrCCHCH₃), 2.67, 2.58

(6H, s, NMe₂), 2.43 (1H, d br., Jꢀ2.2 Hz, OH), 1.57

(3H, d, Jꢀ

6.2 Hz, CrCCHCH₃); ¹³C-NMR DEPT

/

2/8). ¹H-NMR (CDCl₃, 300 MHz) d

CH₂Cl₂/ETPꢀ8/2), 14 mg of complex 12b and 92 mg of

complex 11b were obtained; d.e. after purification: 74%;

yield: 86.3%.

/

8

/

Reaction at ꢃ30 8C. Complex 6: 103 mg (0.29 mmol,

/

one equivalent); dry THF: 4 ml; n-BuLi, 1.61 M: 0.19 ml

(0.31 mmol, 1.05 equivalents); propionaldehyde 10b:

0.045 ml (0.62 mmol, 2.12 equivalents). Crude product:

135 mg; d.e.: 65%. After purification (eluent: CH₂Cl₂/

/

(CDCl₃, 75 MHz) d (ppm): 291.9 (C_carbene), 231.5,

229.3, 219.4, 218.3 (CO), 142.5 (Cq CHOHPh), 133.5

(Cq NCH₂Ph), 129.5ꢂ/125.9 (C Ph), 75.8 (CHOH), 52.2,

ETPꢀ8/2), 16 mg of complex 12b and 77 mg of

/

52.0 (NMe₂), 51.7 (CrCCH), 49.1 (NCH₂Ph), 16.0

(CrCCHCH₃); IR/FT (neat) n (cm^ꢃ1): 3392 (OH),

1998 (trans-CO), 1869, 1829 (cis-CO), 728 (gCH_arom.),

complex 11b were obtained; d.e. after purification:

66%; yield: 77.7%.

679 (dCH_arom.); MS (FAB^ꢁ), m/z 460 [M^ꢁ], 432 [M^ꢁÃ

/

4.4.3.1. (R*,S*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(butyl-1-methyl-2-

CO], 376 [M^ꢁÃ

HNMe₂], 257 [M^ꢁÃ

HNMe₂ÃPhCHO], 107 [PhCHÄ

/

3CO], 348 [M^ꢁÃ

4COÃ

PhCH₂], 197 [M^ꢁÃ

OH^ꢁ], 91 [C₇H₇^ꢁ].

/

4CO], 303 [M^ꢁÃ

/

4COÃ

/

4COÃ

/

hydroxy)carbene]chromium(0) (11b). Complex 11b

(major diastereoisomer): yellow solid; m.p. 114 8C

(CH₂Cl₂/pentane). Anal. Calcd for C₁₉H₂₄CrN₂O₅: C,

/

4.4.2.2. (R*,S*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(ethyl-1-methyl-2-phenyl-2-

55.34; H, 5.87; N, 6.79. Found: C, 55.52; H, 6.02; N,

1

6.91%. Rf: 0.04 (eluent: ETP/CH₂Cl₂ꢀ

(CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

4.80 (1H, d, Jꢀ17 Hz, CH₂Ph), 4.62 (1H, d, Jꢀ

CH₂Ph), 4.0ꢂ3.8 (1H, m, HOCHCH₂), 2.86, 2.80 (6H, s,

NMe₂), 2.62 (1H, quint., Jꢀ6.6 Hz, CrCCHCH₃), 2.1

(1H, s br., OH), 1.65 (1H, ddq, J_vic2.3 Hz, J_gem13.6

Hz, J_vic7 Hz, HOCHCH₂), 1.41 (3H, d, Jꢀ6.6 Hz,

CrCCHCH₃), 1.34 (1H, ddq, J_vic2.3 Hz, J_gem13.6

Hz, J_vic7 Hz, HOCHCH₂), 1.20 (3H, t, Jꢀ7 Hz,

/2/8). H-NMR

hydroxy)carbene]chromium(0) (12a). Complex 12a

(minor diastereoisomer): red viscous oil; Rf: 0.31

/7.1 (5H, m, H_aromat),

/

/17 Hz,

(eluent: ETP/CH₂Cl₂ꢀ

MHz) d (ppm): 7.5ꢂ7.2 (10H, m, H_aromat), 5.11 (1H,

d, Jꢀ17.2 Hz, CH₂Ph), 5.10 (1H, dd, J₁ꢀ9.4 Hz, J₂ꢀ

2.8 Hz, OHCHPh), 4.65 (1H, d, Jꢀ17.2 Hz, CH₂Ph),

2.91 (3H, s, NMe₂), 2.90 (1H, dq, J₁ꢀ9.4 Hz, J₂ꢀ6.6

Hz, CrCCHCH₃), 2.78 (3H, s, NMe₂), 2.30 (1H, d br.,

/

2/8). ¹H-NMR (CDCl₃, 300

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

Jꢀ

/

2.8 Hz, OH), 1.08 (3H, d, Jꢀ

/

6.6 Hz, CrCCHCH₃);

¹³C-NMR DEPT (CDCl₃, 75 MHz) d (ppm): 292.5

(C_carbene), 232.3, 229.6, 219.1, 218.6 (CO), 141.7 (Cq

CH₂CH₃); ¹³C-NMR DEPT (CDCl₃, 75 MHz) d (ppm):

293.0 (C_carbene), 231.5, 229.4, 218.8, 218.2 (CO), 133.5

(Cq NCH₂Ph), 129.4, 128.6, 126.2 (C Ph), 76.2

(CHOH), 52.5, 52.3 (NMe₂), 50.0 (CrCCH), 49.4

(NCH₂Ph), 29.1 (CH₂CH₃), 15.5 (CrCCHCH₃), 10.5

(CH₂CH₃); IR/FT (Nujol) n (cm^ꢃ1): 3383 (OH), 2003

(trans-CO), 1879, 1806 (cis-CO), 741 (gCH_arom.), 680

CHOHPh), 134.0 (Cq NCH₂Ph), 129.5ꢂ126.2 (C Ph),

/

79.1 (CHOH), 52.8, 52.1 (NMe₂), 50.7 (CrCCH), 49.3

(NCH₂Ph), 16.2 (CrCCHCH₃); IR/FT (neat) n (cm^ꢃ1):

3431 (OH), 1998 (trans-CO), 1869, 1827 (cis-CO), 728

(gCH_arom.), 680 (dCH_arom.), MS (FAB^ꢁ), m/z 460

[M^ꢁ], 432 [M^ꢁÃ

3CO], 348 [M^ꢁÃ4CO], 303 [M^ꢁÃ

4COÃPhCH₂], 197

[M^ꢁÃ [M^ꢁÃ

PhCHO], 91 [C₇H₇^ꢁ].

(dCH_arom.), MS (FAB^ꢁ), m/z 412 [M^ꢁ], 384 [M^ꢁÃ

CO], 356 [M^ꢁÃ2CO], 328 [M^ꢁÃ3CO], 300 [M^ꢁÃ

4CO], 255 [M^ꢁÃ HNMe₂], 209 [M^ꢁÃ

4COÃ 4COÃ

PhCH₂], 165 [M^ꢁÃ PhCH₂], 91 [C₇H₇^ꢁ].

4COÃNMe₂Ã

/

CO], 404 [M^ꢁÃ

4COÃ

/

2CO], 376 [M^ꢁÃ

HNMe₂], 257

HNMe₂Ã

/

4.4.3.2. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(butyl-1-methyl-2-

4.4.3. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(butyl-1-methyl-2-

hydroxy)carbene]chromium(0) (11b and 12b)

hydroxy)carbene]chromium(0) (12b). Complex 12b

(minor diastereoisomer): red oil. Rf: 0.1 (eluent: ETP/

1

Reaction at ꢃ

/

78 8C for 3 h 30 min. Complex 6: 103

CH₂Cl₂ꢀ

7.5ꢂ

CH₂Ph), 4.59 (1H, d, Jꢀ

m, HOCHCH₂), 2.86, 2.74 (6H, s, NMe₂), 2.67 (1H, dq,

J₁ꢀ9.2 Hz, J₂ꢀ6.5 Hz, CrCCHCH₃), 2.06 (1H, d, Jꢀ

4.2 Hz, OH), 1.80 (1H, ddq, J_vic2.8 Hz, J_gem14.2

Hz, J_vic7.4 Hz, HOCHCH₂), 1.5ꢂ1.35 (1H, m,

HOCHCH₂), 1.28 (3H, d, Jꢀ6.5 Hz, CrCCHCH₃),

0.99 (3H, t, Jꢀ

7.4 Hz, CH₂CH₃); ¹³C-NMR DEPT

/2/8). H-NMR (CDCl₃, 300 MHz) d (ppm):

mg (0.29 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.64 M: 0.18 ml (0.29 mmol, 1.02 equivalents); propio-

naldehyde 10b: 0.045 ml (0.62 mmol, 2.1 equivalents).

Crude product: 140 mg; d.e.: 73%. After purification

/

7.1 (5H, m, H_aromat), 4.99 (1H, d, Jꢀ

/

17.2 Hz,

4.0 (1H,

/

17.2 Hz, CH₂Ph), 4.2ꢂ

/

(eluent: CH₂Cl₂/ETPꢀ/8/2), 13 mg of complex 12b and

ꢀ

/

ꢀ

/

84 mg of complex 11b were obtained; d.e. after

purification: 74%; yield: 81.2%.

ꢀ

/

Reaction at ꢃ

/

78 8C for 30 min. Complex 6: 106 mg

/

(0.3 mmol, one equivalent); dry THF: 4 ml; n-BuLi, 1.54

M: 0.20 ml (0.31 mmol, 1.03 equivalents); propionalde-

hyde 10b: 0.045 ml (0.62 mmol, 2.07 equivalents). Crude

product: 134 mg; d.e.: 74%. After purification (eluent:

(CDCl₃, 75 MHz) d (ppm): 292.7 (C_carbene), 231.9,

229.4, 218.4 (CO), 133.9 (Cq NCH₂Ph), 129.4, 128.4,

126.1 (C Ph), 76.5 (CHOH), 52.9, 52.2 (NMe₂), 49.3

(NCH₂Ph), 48.6 (CrCCH), 26.8 (CH₂CH₃), 15.9

182

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

(CrCCHCH₃), 9.1 (CH₂CH₃); IR/FT (neat) n (cm^ꢃ1):

3463 (OH), 1998 (trans-CO), 1866 (cis-CO), 728

(gCH_arom.), 680 (dCH_arom.); MS (FAB^ꢁ) m/z 412

11c were obtained; d.e. after purification: 57%; yield:

70%.

[M^ꢁ], 384 [M^ꢁÃ

3CO]; 300 [M^ꢁÃ4CO], 255 [M^ꢁÃ

[M^ꢁÃ PhCH₂], 165 [M^ꢁÃ

4COÃ 4COÃ

91 [C₇H₇^ꢁ].

/

CO], 356 [M^ꢁÃ

4COÃ

NMe₂Ã

/

2CO], 328 [M^ꢁÃ

HNMe₂], 209

PhCH₂],

/

4.4.4.1. (R*,S*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(butyl-1,3-dimethyl-2-

hydroxy)carbene]chromium(0) (11c). Complex 11c

(major diastereoisomer): yellow solid; m.p. 130 8C

(CH₂Cl₂/pentane). Anal. Calcd for C₂₀H₂₆CrN₂O₅: C,

/

56.33; H, 6.15; N, 6.57. Found: C, 56.25; H, 6.36; N,

1

4.4.4. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(butyl-1,3-dimethyl-2-

hydroxy)carbene]chromium(0) (11c and 12c)

6.91%. Rf: 0.08 (eluent: ETP/CH₂Cl₂ꢀ

(CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

4.73 (1H, d, Jꢀ17 Hz, CH₂Ph), 4.65 (1H, d, Jꢀ

CH₂Ph), 3.89 (1H, d br., Jꢀ6.6 Hz, HOCHCH), 2.86,

2.83 (6H, s, NMe₂), 2.73 (1H, quint., Jꢀ6.6 Hz,

CrCCHCH₃), 2.06 (1H, s br., OH), 1.78 (1H, set.d,

J₁ꢀ2.9 Hz, J₂ꢀ6.7 Hz, HOCHCH), 1.33 (3H, d, Jꢀ

6.6 Hz, CrCCHCH₃), 1.00 (3H, d, Jꢀ6.7 Hz,

CH(CH₃)₂), 0.82 (3H, d, Jꢀ

6.7 Hz, CH(CH₃)₂); ¹³C-

/

2/8). H-NMR

/

7.05 (5H, m, H_aromat),

/

/17 Hz,

Reaction at ꢃ

/

78 8C for 3 h 30 min. Complex 6: 103

/

mg (0.29 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.64 M: 0.18 ml (0.29 mmol, 1.01 equivalents); isobutyr-

aldehyde 10c: 0.055 ml (0.60 mmol, 2.06 equivalents).

Crude product: 154 mg; d.e.: 93%. After purification

/

(eluent: CH₂Cl₂/ETPꢀ/8/2), 4 mg of complex 12c and

/

100 mg of complex 11c were obtained; d.e. after

purification: 93%; yield: 83.3%.

NMR DEPT (CDCl₃, 75 MHz) d (ppm): 293.7 (C_car-

_bene), 231.1, 229.4, 218.7, 218.2 (CO), 133.4 (Cq

NCH₂Ph), 129.5, 128.7, 126.2 (C Ph), 78.4 (CHOH),

52.5, 52.3 (NMe₂), 49.6 (NCH₂Ph), 46.8 (CrCCH), 31.4

Reaction at ꢃ78 8C for 30 min (concentration of

/

carbene enolate: 0.071 M). Complex 6: 103 mg (0.29

mmol, one equivalent); dry THF: 4 ml; n-BuLi, 1.52 M:

0.19 ml (0.29 mmol, one equivalent); isobutyraldehyde

10c: 0.055 ml (0.60 mmol, 2.1 equivalents). Crude

product: 128 mg; d.e.: 91%. After purification (eluent:

(CH(CH₃)₂),

20.2

(CrCCHCH₃),

15.5,

14.8

(CH(CH₃)₂); IR/FT (Nujol) n (cm^ꢃ1): 3393 (OH),

1999 (trans-CO), 1890, 1861, 1821 (cis-CO), 734

(gCH_arom.), 680 (dCH_arom.); MS (FAB^ꢁ) m/z 426

CH₂Cl₂/ETPꢀ/8/2), 4 mg of complex 12c and 109 mg of

[M^ꢁ], 398 [M^ꢁÃ

3CO], 326 [M^ꢁÃ

2COÃ

[M^ꢁÃ PhCH₂], 298 [M^ꢁÃ

COÃ

[M^ꢁÃ [M^ꢁÃ

4COÃNMe₂], 197

(CH₃)₂CHCHO], 179 [M^ꢁÃ

4COÃPhCH₂Ã

[M^ꢁÃ

4COÃHNMe₂ÃPhCH₂Ã(CH₃)₂CHCHO],

[C₇H₇^ꢁ].

/

CO], 370 [M^ꢁÃ

NMe₂], 314 [M^ꢁÃ

3COÃNMe₂], 270

4COÃHNMe₂Ã

NMe₂], 107

91

/

2CO], 342 [M^ꢁÃ

/

complex 11c were obtained; d.e. after purification: 93%;

yield: 92.6%.

/

4CO], 307

/

Reaction at ꢃ

/

78 8C for 30 min (concentration of

/

carbene enolate: 0.3 M). Complex 6: 400 mg (1.13 mmol,

one equivalent); dry THF: 3 ml; n-BuLi, 1.54 M: 0.74 ml

(1.14 mmol, 1.01 equivalents); isobutyraldehyde 10c:

0.205 ml (2.26 mmol, two equivalents). Crude product:

529 mg; d.e.: 93%. After purification (eluent: CH₂Cl₂/

/

4.4.4.2. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(butyl-1,3-dimethyl-2-

ETPꢀ/8/2), 18 mg of complex 12c and 386 mg of

complex 11c were obtained; d.e. after purification: 91%;

yield: 83.7%.

hydroxy)carbene]chromium(0) (12c). Complex 12c

(minor diastereoisomer): orange solid; m.p. 120 8C

(CH₂Cl₂/pentane). Anal. Calcd for C₂₀H₂₆CrN₂O₅: C,

Reaction at ꢃ78 8C for 3 h 30 min in the presence of

/

Kriptofix 221. Complex 6: 106 mg (0.3 mmol, one

equivalent); dry THF: 3 ml; n-BuLi, 1.544 M: 0.2 ml (0.3

mmol, one equivalent). After anion formation, 1 ml of

Kriptofix 221 solution in THF (100 mg, 90%, 0.31

mmol, one equivalent) was added; isobutyraldehyde 10c:

0.055 ml (0.6 mmol, two equivalents). Crude product:

277 mg; d.e.: 70%. After purification (eluent: CH₂Cl₂/

56.33; H, 6.15; N, 6.57. Found: C, 55.92; H, 5.99; N,

1

6.36%. Rf: 0.12 (eluent: ETP/CH₂Cl₂ꢀ

(CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

4.98 (1H, d, Jꢀ17.1 Hz, CH₂Ph), 4.58 (1H, d, Jꢀ

Hz, CH₂Ph), 4.01 (1H, ddd, J₁ꢀ9.5 Hz, J₂ꢀ4.4 Hz,

J₃ꢀ2 Hz, HOCHCH), 2.87 (3H, s, NMe₂), 2.76 (1H,

dq, J₁ꢀ9.5 Hz, J₂ꢀ6.5 Hz, CrCCHCH₃), 2.75 (3H, s,

NMe₂), 2.00 (1H, set.d, J₁ꢀ2 Hz, J₂ꢀ6.9 Hz,

HOCHCH), 1.83 (1H, d, Jꢀ4.4 Hz, OH), 1.24 (3H,

d, Jꢀ6.5 Hz, CrCCHCH₃), 1.05 (3H, d, Jꢀ6.9 Hz,

CH(CH₃)₂), 0.77 (3H, d, Jꢀ

6.9 Hz, CH(CH₃)₂); ¹³C-

/2/8). H-NMR

/7.15 (5H, m, H_aromat),

/

/17.1

/

ETPꢀ/8/2), 81 mg of complex 12c and 14.5 mg of

/

complex 11c were obtained; d.e. after purification: 69%;

yield: 75%. The reaction was slower than the same

reaction without Kriptofix (TLC monitoring).

/

Reaction at ꢃ

/

30 8C. Complex 6: 100 mg (0.28 mmol,

NMR DEPT (CDCl₃, 75 MHz) d (ppm): 293.1 (C_car-

_bene), 232.1, 229.5, 219.5, 218.5 (CO), 134.1 (Cq

NCH₂Ph), 129.4, 128.4, 126.2 (C Ph), 79.1 (CHOH),

52.8, 52.1 (NMe₂), 49.4 (NCH₂Ph), 46.3 (CrCCH), 28.7

one equivalent); dry THF: 4 ml; n-BuLi, 1.64 M: 0.18 ml

(0.3 mmol, 1.05 equivalents); isobutyraldehyde 10c:

0.055 ml (0.60 mmol, 2.14 equivalents). Crude product:

135 mg; d.e.: 58%. After purification (eluent: CH₂Cl₂/

(CH(CH₃)₂),

20.1

(CrCCHCH₃),

15.3,

13.8

ETPꢀ8/2), 18 mg of complex 12c and 66 mg of complex

/

(CH(CH₃)₂); IR/FT (neat) n (cm^ꢃ1): 3468 (OH), 1997

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

/

188

183

(trans-CO), 1865 (cis-CO), 730 (gCH_arom.), 679

(dCH_arom.); MS (FAB^ꢁ) m/z 426 [M^ꢁ], 398 [M^ꢁÃ

CO], 370 [M^ꢁÃ2CO], 342 [M^ꢁÃ3CO], 314 [M^ꢁÃ

4CO], 307 [M^ꢁÃ PhCH₂], 299 [M^ꢁÃ

COÃ 3COÃCH₂Ä

Nme], 269 [M^ꢁÃ HNMe₂], 197 [M^ꢁÃ

4COÃ 4COÃ

HNMe₂Ã 4COÃPhCH₂Ã

(CH₃)₂CHCHO], 179 [M^ꢁÃ

NMe₂], 107 4COÃHNMe₂ÃPhCH₂Ã

[M^ꢁÃ

(CH₃)₂CHCHO], 91 [C₇H₇^ꢁ].

231.7, 229.3, 219.4, 218.2 (CO), 136.2 (Cq CHÄ

133.4 (Cq NCH₂Ph), 132.1 (CHÄ

128.6, 128.4, 127.9, 126.6, 126.0 (C Phꢁ

75.5 (CHOH), 52.6, 52.1 (NMe₂), 50.4 (CrCCH), 49.4

(NCH₂Ph), 16.3 (CrCCHCH₃); IR/FT (neat) n (cm^ꢃ1):

3388 (OH), 1997 (trans-CO), 1865, 1807 (cis-CO), 752

(gCH_arom.), 679 (dCH_arom.); MS (FAB^ꢁ) m/z 486

/

CHPh),

/

CHPh), 129.8, 129.4,

/

CHÄCHPh),

/

[M^ꢁ], 458 [M^ꢁÃ

3CO], 374 [M^ꢁÃ4CO], 329 [M^ꢁÃ

PhCH₂], 238

[M^ꢁÃ

4COÃNHMe₂ÃPhCHÄ

/

CO], 430 [M^ꢁÃ

4COÃ

CHCHO],

/

2CO], 402 [M^ꢁÃ

NHMe₂], 283

HNMe₂Ã

/

4.4.5. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(but-3-enyl-2-hydroxy-1-methyl-

4-phenyl)carbene]chromium(0) (11d and 12d) and

(R*,R*)-tetracarbonyl[(N-benzyl-N?,N?-

[M^ꢁÃ

/

4COÃ

/

PhCH₂],197

91 [C₇H₇^ꢁ].

/

dimethylhydrazinyl)-1-(propyl-1-methyl-2-phenyl-3-

carboxaldehyde)carbene]chromium(0) (13)

4.4.5.2. (R*,R*,E)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(but-3-enyl-2-hydroxy-1-methyl-

Reaction at ꢃ

/

78 8C for 3 h 30 min. Complex 6: 109

4-phenyl)carbene]chromium(0) (12d). Complex 12d

(minor diastereoisomer): red viscous oil; Rf: 0.23

mg (0.31 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.58 M: 0.20 ml (0.32 mmol, 1.03 equivalents); cinna-

maldehyde 10d: 0.08 ml (0.64 mmol, 2.1 equivalents).

(eluent: ETP/CH₂Cl₂ꢀ

MHz) d (ppm): 7.5ꢂ7.2 (10H, m, H_aromat), 6.73 (1H,

d, Jꢀ15.8 Hz, CHÄCHPh), 6.18 (1H, dd, J₁ꢀ15.8 Hz,

J₂ꢀ7.93 Hz, CH ÄCHPh), 5.08 (1H, d, Jꢀ17.3 Hz,

CH₂Ph), 4.8ꢂ4.6 (1H, m, HOCH), 4.62 (1H, d, Jꢀ17.3

Hz, CH₂Ph), 2.89 (3H, s, NMe₂), 2.76 (1H, dq, J₁ꢀ9.1

Hz, J₂ꢀ6.6 Hz, CrCCHCH₃), 2.75 (3H, s, NMe₂), 2.14

/

3/7). ¹H-NMR (CDCl₃, 300

/

Crude product: 188.5 mg; d.e. ꢀ

(eluent: CH₂Cl₂/ETPꢀ8/2), 5 mg of complex 13, 5 mg

of complex 12d, and 95 mg of complex 11d were

obtained; d.e. after purification ꢀ98%; yield: 63.3%;

yield Michael adduct 13: 3.6% single diastereoisomer.

Reaction at ꢃ78 8C for 30 min. Complex 6: 103 mg

/98%. After purification

/

(1H, d, Jꢀ

/

2.9 Hz, OH), 1.31 (3H, d, Jꢀ6.6 Hz,

/

(0.29 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.54 M: 0.19 ml (0.29 mmol, one equivalent); cinnamal-

dehyde 10d: 0.075 ml (0.60 mmol, two equivalents).

Crude product: 179 mg; d.e.: 90%. After purification

CrCCHCH₃); ¹³C-NMR DEPT (CDCl₃, 75 MHz) d

(ppm): 292.6 (C_carbene), 232.2, 229.6, 219.1, 218.5 (CO),

136.1 (Cq CHÄ

(CHÄCHPh), 129.4, 129.1, 128.6, 128.4, 128.0, 126.6,

126.1 (C PhꢁCHÄCHPh), 77.8 (CHOH), 52.8, 52.1

/

CHPh), 133.9 (Cq NCH₂Ph), 133.6

/

(eluent: CH₂Cl₂/ETPꢀ

complex 12d, and 114 mg of complex 11d were obtained;

d.e. after purification ꢀ98%; yield: 80%; yield Michael

adduct 13: 3% single diastereoisomer.

Reaction at ꢃ30 8C. Complex 6: 150 mg (0.42 mmol,

/8/2) 4 mg of complex 13, 4 mg of

/

(NMe₂), 49.2 (NCH₂Ph), 49.0 (CrCCH), 16.3

(CrCCHCH₃); IR/FT (neat) n (cm^ꢃ1): 3391 (OH),

1998 (trans-CO), 1868, 1827 (cis-CO), 753 (gCH_arom.),

/

683 (dCH_arom.); MS (FAB^ꢁ) m/z 486 [M^ꢁ], 458 [M^ꢁÃ

/

one equivalent); dry THF: 4 ml; n-BuLi, 1.58 M: 0.27 ml

(0.43 mmol, one equivalent); cinnamaldehyde 10d: 0.11

ml (0.87 mmol, 2.1 equivalents). Crude product: 255 mg;

CO], 430 [M^ꢁÃ

329 [M^ꢁÃ

4COÃ

[M^ꢁÃ

4COÃHNMe₂Ã

NHMe₂ÃPhCHÄ

/

2CO], 402 [M^ꢁÃ

/

3CO], 374 [M^ꢁÃ

4COÃPhCH₂], 238

[M^ꢁÃ

4COÃ

/

4CO],

/

NHMe₂], 283 [M^ꢁÃ

/

PhCH₂],197

/

d.e.: 18%. After purification (eluent: CH₂Cl₂/ETPꢀ

/8/

/

CHCHO], 91 [C₇H₇^ꢁ].

2), 36 mg of complex 13, 19 mg of complex 12d, and 45

mg of complex 11d were obtained; d.e. after purification:

42%; yield: 31.1%; yield Michael adduct 13: 17.5% single

diastereoisomer.

4.4.5.3. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(propyl-1-methyl-2-phenyl-3-

carboxaldehyde)carbene]chromium(0) (13). Complex

13 (from Michael addition): red viscous oil; Rf: 0.3

4.4.5.1. (R*,S*,E)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(but-3-enyl-2-hydroxy-1-methyl-

4-phenyl)carbene]chromium(0) (11d). Complex 11d

(major diastereoisomer): red viscous oil; Rf: 0.01

(eluent: ETP/CH₂Cl₂ꢀ

MHz) d (ppm): 9.60 (1H, m, CHO), 7.4ꢂ

_aromat), 4.17 (1H, d, Jꢀ17.2 Hz, CH₂Ph), 4.02 (1H, d,

Jꢀ17.2 Hz, CH₂Ph), 3.80 (1H, td, J₁ꢀ

Hz, CHCHPh), 3.06 (1H, ddd, J₁ꢀ16.4 Hz, J₂ꢀ

Hz, J₃ꢀ1 Hz, CH₂CO), 2.94 (1H, dq, J₁ꢀ

6.5 Hz, CH₃CH), 2.74 (1H, ddd, J₁ꢀ16.4 Hz, J₂ꢀ

Hz, J₃ꢀ3.1 Hz, CH₂CO), 2.60, 2.53 (6H, s, NMe₂), 1.49

(1H, d, Jꢀ

6.5 Hz, CH₃CH); ¹³C-NMR DEPT (CDCl₃,

/

3/7). ¹H-NMR (CDCl₃, 300

/6.9 (10H, m,

H

/

10 Hz, J₂ꢀ

/

4.8

(eluent: ETP/CH₂Cl₂ꢀ

MHz) d (ppm): 7.5ꢂ7.0 (10H, m, H_aromat), 6.82 (1H,

d, Jꢀ16 Hz, CHÄCHPh), 6.45 (1H, dd, J₁ꢀ16 Hz,

J₂ꢀ6.9 Hz, CH ÄCHPh), 4.82 (1H, d, Jꢀ17.2 Hz,

CH₂Ph), 4.8ꢂ4.6 (1H, m, HOCH), 4.59 (1H, d, Jꢀ17.2

Hz, CH₂Ph), 2.87 (1H, dq, J₁ꢀ8 Hz, J₂ꢀ6.5 Hz,

CrCCHCH₃), 2.76, 2.75 (6H, s, NMe₂), 2.06 (1H, s br.,

OH), 1.52 (3H, d, Jꢀ

6.5 Hz, CrCCHCH₃); ¹³C-NMR

DEPT (CDCl₃, 75 MHz) d (ppm): 291.4 (C_carbene),

/

3/7). ¹H-NMR (CDCl₃, 300

/

/4.8

/

10 Hz, J₂ꢀ

/

10

/

75 MHz) d (ppm): 293.8 (C_carbene), 232.1, 229.2, 219.8,

218.8 (CO), 201.0 (CHO), 141.9, 133.5 (Cq Ph), 129.5,

128.9, 128.5, 127.5, 125.8 (C Ph), 52.4, 51.9 (NMe₂), 49.0

(CH₂Ph), 48.6 (CrCCH), 46.5 (CH₂CO), 44.3 (CHPh),

/

184

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

18.4 (CH₃). IR/FT (neat) n (cm^ꢃ1): 2728 (overtone

CHO), 1997 (trans-CO), 1866, 1829 (cis-CO), 1723

(CHO), 723 (gCH_arom.), MS (FAB^ꢁ) m/z 486 [M^ꢁ],

¹H-NMR (CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

_aromat), 5.12 (1H, d, Jꢀ17.3 Hz, CH₂Ph), 4.67 (1H, d,

Jꢀ9.1 Hz, OHCHCp), 4.54 (1H, d, Jꢀ17.3 Hz,

CH₂Ph), 4.4ꢂ4.1 (9H, m, Cp), 2.94, 2.71 (6H, s,

NMe₂), 2.57 (1H, dq, J₁ꢀ9.1 Hz, J₂ꢀ6.5 Hz,

CrCCHCH₃), 2.32 (1H, d, Jꢀ1.3 Hz, OH), 1.14 (3H,

d, Jꢀ

6.5 Hz, CrCCHCH₃); ¹³C-NMR DEPT (CDCl₃,

/

7.1 (5H, m,

H

/

458 [M^ꢁÃ

[M^ꢁÃ4CO], 329 [M^ꢁÃ

4COÃ

PhCH₂], 239 [M^ꢁÃ

[M^ꢁÃ

4COÃNMe₂ÃPhCHÄ

/

CO], 430 [M^ꢁÃ

4COÃ

CHCHO], 91 [C₇H₇^ꢁ].

/

2CO], 402 [M^ꢁÃ

NHMe₂], 283 [M^ꢁÃ

NMe₂ÃPhCH₂], 198

/

3CO], 374

/

75 MHz) d (ppm): 292.5 (C_carbene), 232.5, 229.8, 218.9,

218.7 (CO), 134.2 (Cq NCH₂Ph), 129.4, 128.3, 126.0 (C

Ph), 94.1 (Cq Cp), 74.4 (CHOH), 69.7, 68.4, 68.1, 64.2

(Cp), 52.6, 52.1 (NMe₂), 50.8 (CrCCH), 49.1

4.4.6. Synthesis of tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(ethyl-1-methyl-2-ferrocenyl-2-

hydroxy)carbene]chromium(0) (11e and 12e)

Reaction at ꢃ

/

78 8C for 3 h 30 min. Complex 6: 107

(NCH₂Ph), 16.3 (CrCCHCH₃); IR/FT (neat)

n

mg (0.3 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.54 M: 0.20 ml (0.31 mmol, one equivalent); ferroce-

nylaldehyde 10e: 128 mg (0.6 mmol, two equivalents).

Crude product: 243 mg; d.e.: 52%. After purification

(eluent: CH₂Cl₂), 30 mg of complex 12e and 101 mg of

complex 11e were obtained; d.e. after purification: 54%;

yield: 76.7%.

(cm^ꢃ1): 3584 (OH), 1997 (trans-CO), 1869, 1827 (cis-

CO), 730 (gCH_arom.), 681 (dCH_arom.).

4.5. Oxidations

We used general procedures previously published [13]

for the oxidation of hydrazinocarbene complexes.

Reaction at ꢃ78 8C for 30 min. Complex 6: 103 mg

/

(0.29 mmol, one equivalent); dry THF: 4 ml; n-BuLi,

1.54 M: 0.19 ml (0.29 mmol, one equivalent); ferroce-

nylaldehyde 10e: 127 mg (0.59 mmol, two equivalents).

Crude product: 236 mg; d.e.: 90%. After purification

(eluent: CH₂Cl₂), 6 mg of complex 12e and 133 mg of

complex 11e were obtained; d.e. after purification: 91%;

yield: 84%.

4.5.1. Synthesis of (R*,R*)-2-(3-oxo-cyclohexyl)-

propionic acid N-benzyl-N?,N?-dimethyl-hydrazide (13b)

Hydrazinocarbene complex 9b: 107 mg (0.24 mmol,

one equivalent); K₂HPO₄: 422 mg (2.4 mmol, 10

equivalents); KH₂PO₄: 329 g (2.4 mmol, 10 equivalents);

TBAB: 4.7 mg (0.01 mmol, 4.2 mol%); Ca(OCl)₂: 78 mg

(0.35 mmol, 1.4 equivalents); water: 5 ml; AcOEt: 5 ml;

after work-up, 66 mg of the hydrazide 13b was obtained;

yield 92%.

4.4.6.1. (R*,S*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(ethyl-1-methyl-2-ferrocenyl-2-

hydroxy)carbene]chromium(0) (11e). Complex 11e

(major diastereoisomer): orange solid; m.p. 112ꢂ

/

113 8C (Et₂O/hexane). Anal. Calcd for

C₂₇H₂₈CrFeN₂O₅: C, 57.06; H, 4.97; N, 4.93. Found:

C, 56.92; H, 5.13; N, 4.81%. Rf: 0.29 (eluent: CH₂Cl₂).

4.5.2. (R*,R*)-2-(3-Oxo-cyclohexyl)-propionic acid N-

benzyl-N?,N?-dimethyl-hydrazide (13b)

Complex 13b: colourless oil. Rf: 0.71 (eluent: MTBE).

¹H-NMR (CDCl₃, 300 MHz) d (ppm): 7.4ꢂ

/

6.85 (5H, m,

8.9 Hz, OHCHCp), 4.3ꢂ

CH₂Ph), 4.03 (1H, d, Jꢀ17.3 Hz,

CH₂Ph), 2.69 (1H, dq, J₁ꢀ8.9 Hz, J₂ꢀ6.3 Hz,

CrCCHCH₃), 2.68, 2.58 (6H, s, NMe₂), 2.36 (1H, d,

Jꢀ1.2 Hz, OH), 1.63 (3H, d, Jꢀ6.3 Hz, CrCCHCH₃);

H_aromat), 4.62 (1H, d br., Jꢀ

/

4.15 (10H, m, Cpꢁ

/

HRMS (EI) for C₁₈H₂₆N₂O₂: [M^ꢁ] calc.: 302.19943,

/

found: 302.1977; [Mꢁ

1^ꢁ] calc.: 303.20725, found:

/

1

303.2063. H-NMR (CDCl₃, 300 MHz) d (ppm): 7.5ꢂ

7.1 (5H, m, CH_arom.), 4.65 (1H, d, Jꢀ15.8 Hz, CH₂Ph),

4.59 (1H, d, Jꢀ15.8 Hz, CH₂Ph), 3.5ꢂ3.3 (1H, m,

CHMe), 2.49 (6H, s, NMe₂), 2.6ꢂ1.3 (9H, m, cycloesa-

none), 1.10 (3H, d, Jꢀ

6.6 Hz, CrCCHCH₃); ¹³C-NMR

/

¹³C-NMR DEPT (CDCl₃, 75 MHz) d (ppm): 291.8

(C_carbene), 231.8, 229.5, 220.3, 218.4 (CO), 133.7 (Cq

NCH₂Ph), 129.4, 128.3, 125.7 (C Ph), 93.6 (Cq Cp), 70.9

(CHOH), 68.8, 68.6, 68.0, 64.3 (Cp), 52.5 (NMe₂), 52.1

(CrCCH), 49.1 (NCH₂Ph), 17.9 (CrCCHCH₃); IR/FT

(neat) n (cm^ꢃ1): 3565 (OH), 1996 (trans-CO), 1866,

1833 (cis-CO), 736 (gCH_arom.), 685 (dCH_arom.).

/

DEPT (CDCl₃, 75 MHz) d (ppm): 211.6 (CO ketone),

178.2 (CO hydrazide), 139.4 (C_qPh), 128.4, 127.4, 126.8

(C Ph), 45.1 (CHCH₂CO), 44.8 (NMe₂), 41.4

(CH₂CH₂CO), 41.3 (CHCON), 39.8 (CHCH₂CO),

29.8 (CH₂CH₂CO), 25.0 (CHCH₂CH₂), 15.4 (CH₃).

4.4.6.2. (R*,R*)-Tetracarbonyl[(N-benzyl-N?,N?-

dimethylhydrazinyl)-1-(ethyl-1-methyl-2-ferrocenyl-2-

hydroxy)carbene]chromium(0) (12e). Complex 12e

IR/FT (neat) n (cm^ꢃ1): 1708 (nCÄ

O hydrazide), 1496 (arCÃC), 1350 (dsy CH₃), 730

(gCH_arom.), 699 (dCH_arom.). MS (EI) m/z 303 [M^ꢁꢁ

1], 302 [M^ꢁ], 259 [M^ꢁꢁ NMe₂], 211 [M^ꢁÃ

1Ã PhCH₂],

150 [M^ꢁꢁ COR], 149 [M^ꢁÃCOR], 106 [M^ꢁꢁ

1Ã 1Ã

CORÃ

NMe₂], 91 [C₇H₇^ꢁ], 79 [C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65

[C₅H₅^ꢁ].

/

O ketone), 1650 (nCÄ

/

(minor diastereoisomer): orange solid; m.p. 125ꢂ

/

126 8C (Et₂O/hexane). Anal. Calcd for

C₂₇H₂₈CrFeN₂O₅: C, 57.06; H, 4.97; N, 4.93. Found:

C, 56.90; H, 5.15; N, 4.87%. Rf: 0.47 (eluent: CH₂Cl₂).

/

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

/

188

185

4.5.3. Synthesis of (R*,R*)-2-methyl-5-oxo-3,5-

diphenyl-pentanoic acid N-benzyl-N?,N?-dimethyl-

hydrazide (13c)

Hydrazinocarbene complex 9c: 204 mg (0.36 mmol,

one equivalent); K₂HPO₄: 635 mg (3.6 mmol, 10

equivalents); KH₂PO₄: 496 mg (3.6 mmol, 10 equiva-

lents); TBAB: 7 mg (0.015 mmol, 4.2 mol%); Ca(OCl)₂:

202 mg (0.92 mmol, 2.5 equivalents); water: 10 ml;

AcOEt: 10 ml; after work-up, 145 mg of hydrazide 13c

was obtained; yield 96.5%.

(NCH₂Ph), 35.4 (CHCON), 30.3 (CHMe₂), 19.3, 18.8

(CHMe₂), 10.1 (NCOCHCH₃). IR/FT (neat) n (cm^ꢃ1):

3446 (nOH), 1631 (nCÄ

CH₃), 729 (gCH_arom.), 700 (dCH_arom.). MS (EI) m/z 279

[M^ꢁꢁ1], 278 [M^ꢁ], 235 [M^ꢁꢁ NMe₂], 217 [M^ꢁꢁ

1Ã

1ÃNMe₂Ã 1Ã

H₂O], 187 [M^ꢁÃPhCH₂], 150 [M^ꢁꢁ

COCHMeCOHCHMe₂], 149 [100%, M^ꢁÃ

COCHMe-

/

O), 1497 (arCÃ/C), 1353 (dsy

/

COHCHMe₂], 106 [M^ꢁꢁ

/

1Ã

/

COCHMeCOHCHMe₂Ã

/

NMe₂], 91 [C₇H₇^ꢁ], 79 [C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65 [C₅H₅^ꢁ].

4.5.7. Synthesis of (R*,R*)-3-hydroxy-2,4-dimethyl-

pentanoic acid N-benzyl-N?,N?-dimethyl-hydrazide (15c)

Hydrazinocarbene complex 12c: 129 mg (0.30 mmol,

one equivalent); KH₂PO₄: 415 mg (3.05 mmol, 10.1

4.5.4. (R*,R*)-2-Methyl-5-oxo-3,5-diphenyl-pentanoic

acid N-benzyl-N?,N?-dimethyl-hydrazide (13c)

Complex 13c: white solid, m.p. 144 8C (Et₂O/hexane).

Anal. Calcd for C₂₇H₃₀N₂O₂: C, 78.23; H, 7.29; N, 6.76.

Found: C, 78.44; H, 7.51; N, 6.46%. Rf: 0.75 (eluent:

equivalents); NaBO₃×

/

4H₂O: 239 mgꢁ82 mg after 1 h 30

/

1

min (2.08 mmol, 5ꢁ1.8 equivalents); KI: 0.09 ml (0.1 M,

/

MTBE). H-NMR (CDCl₃, 300 MHz) d (ppm): 7.87

0.009 mmol, 3 mol%); water: 10 ml; AcOEt: 10 ml; 78

mg of hydrazide 15c was obtained; yield 92%.

(2H, d, Jꢀ

CH_arom.), 4.74 (1H, d, Jꢀ

Jꢀ15.9 Hz, CH₂Ph), 4.15ꢂ

3.8 (1H, m, CHMe), 3.6ꢂ3.3 (2H, m, CH₂CO), 2.54

6.3

/

7.4 Hz, COPh_{arom. ortho}), 7.6ꢂ

15.9 Hz, CH₂Ph), 4.27 (1H, d,

4.0 (1H, m, CHPh), 3.95ꢂ

/

6.7 (13H, m,

/

4.5.8. (R*,R*)-3-Hydroxy-2,4-dimethyl-pentanoic acid

N-benzyl-N?,N?-dimethyl-hydrazide (15c)

Complex 15c: colourless oil. Rf: 0.04 (eluent:

CH₂Cl₂). HRMS (EI) for C₁₆H₂₆N₂O₂: [M^ꢁ] calc.:

278.19943, found: 278.1991. ¹H-NMR (CDCl₃, 300

(3H, s, NMe₂), 2.26 (3H, s, NMe₂), 1.28 (3H, d, Jꢀ

/

Hz, CHMe); ¹³C-NMR DEPT (CDCl₃, 75 MHz) d

(ppm): 199.0 (COPh), 177.5 (CO), 143.5, 138.9, 137.3

(C_qPh), 133ꢂ

(CHPh), 41.3 (NCH₂Ph), 1.0 (CH₂CO), 40.5

(CHCON), 15.5 (NCOCHCH₃). IR/FT (neat)

(cm^ꢃ1): 1686 (nCÄ

O ketone), 1650 (nCÄO hydrazide),

1495 (arCÃC), 1353 (dsy CH₃), 740 (gCH_arom.), 703

(dCH_arom.).

/126 (C Ph), 44.9, 44.5 (NMe₂), 43.8

MHz) d (ppm): 7.4ꢂ

d, Jꢀ16.2, CH₂Ph), 4.59 (1H, d, Jꢀ

(1H, dq, J_MeÃCHCON7 Hz, J_CHÃCHOH

CHMe), 3.25 (1H, dd, J_CHÃCHMe7 Hz, J_CHÃCHO

4.4 Hz, CHOH), 2.53 (3H, s, NMe₂), 2.51 (3H, s,

NMe₂), 1.8ꢂ1.5 (1H, s broad, OH), 1.8ꢂ1.6 (1H, m,

CHMe₂), 1.29 (3H, d, J_MeÃCHCON7 Hz, MeCH-

CON), 1.00 (3H, d, J_{Me CH}6.7 Hz, Me₂CH), 0.93

7 Hz, Me₂CH); ¹³C-NMR DEPT

/

7.1 (5H, m, CÃ

16.2, CH₂Ph), 3.70

4.4 Hz,

/

H_arom.), 4.65 (1H,

n

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

2

/

4.5.5. Synthesis of (R*,S*)-3-hydroxy-2,4-dimethyl-

pentanoic acid N-benzyl-N?,N?-dimethyl-hydrazide (14c)

Hydrazinocarbene complex 11c: 249 mg (0.58 mmol,

one equivalent); KH₂PO₄: 797 mg (5.8 mmol, 10

ꢀ

/

ꢀ

/

2

(3H, d, J_{Me CH}

ꢀ

/

2

(CDCl₃, 75 MHz) d (ppm): 179.9 (CO), 138.9 (C_q

NCH₂Ph), 128.4, 127.3, 126.8 (C Ph), 80.1 (COH),

44.9, 44.8 (NMe₂), 41.2 (NCH₂Ph), 36.3 (CHCON),

32.3 (CHMe₂), 19.8, 18.2 (CHMe₂), 16.35

(NCOCHCH₃). IR/FT (neat) n (cm^ꢃ1): 3430 (nOH),

equivalents); NaBO₃×/4H₂O: 459 mg (2.98 mmol, five

equivalents); KI: 0.17 ml (0.1 M, 0.017 mmol, 3 mol%);

water: 16 ml; AcOEt: 16 ml; 144 mg of hydrazide 14c

was obtained; yield 88.9%.

1626 (nCÄ

727(gCH_arom.), 700 (dCH_arom.). MS (EI) m/z 279

[M^ꢁꢁ1], 278 [M^ꢁ], 235 [M^ꢁꢁ NMe₂], 217 [M^ꢁꢁ

1Ã

1ÃNMe₂Ã 1Ã

H₂O], 187 [M^ꢁÃPhCH₂], 150 [M^ꢁꢁ

COCHMeCOHCHMe₂], 149 [100%, M^ꢁÃ

COCHMe-

/

O), 1497 (arCÃ

/

C), 1353 (dsy CH₃),

4.5.6. (R*,S*)-3-Hydroxy-2,4-dimethyl-pentanoic acid

N-benzyl-N?,N?-dimethyl-hydrazide (14c)

Complex 14c: colourless oil. Rf: 0.1 (eluent: CH₂Cl₂).

HRMS (EI) for C₁₆H₂₆N₂O₂: [M^ꢁ] calc.: 278.19943,

found: 278.1989. ¹H-NMR (CDCl₃, 300 MHz) d (ppm):

/

COHCHMe₂], 106 [M^ꢁꢁ

/

1Ã

/

COCHMeCOHCHMe₂Ã

/

NMe₂], 91 [C₇H₇^ꢁ], 79 [C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65 [C₅H₅^ꢁ].

7.4ꢂ

CH₂Ph), 4.59 (1H, d, Jꢀ

J_MeÃCHCON7.3 Hz, J_CHÃCHOH

(1H, dd, J_CHÃCHMe8.8 Hz, J_CHÃCHO

2.2 (1H, s very broad, OH), 2.51 (3H, s,

NMe₂), 2.48 (3H, s, NMe₂), 1.82ꢂ1.65 (1H, m, CHMe₂),

1.16 (3H, d, J_MeÃCHCON7.3 Hz, MeCHCON), 1.05

(3H, d, J_{Me CH}6.6 Hz, Me₂CH), 0.87 (3H, d,

7 Hz, Me₂CH); ¹³C-NMR DEPT (CDCl₃, 75

/

7.1 (5H, m, CÃ

/

H aromatic), 4.66 (1H, d, Jꢀ

16 Hz, CH₂Ph), 3.66 (1H, dq,

2.2 Hz, CHMe), 3.41

2.2 Hz,

/

16 Hz,

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

4.5.9. Synthesis of (R*,S*)-3-hydroxy-2-methyl-

pentanoic acid N-benzyl-N?,N?-dimethyl-hydrazide (14b)

Hydrazinocarbene complex 11b: 309 mg (0.75 mmol,

one equivalent); KH₂PO₄: 1.024 g (7.53 mmol, 10.1

2

CHOH), 2.8ꢂ

/

ꢀ

/

ꢀ

/

equivalents); NaBO₃×

/

4H₂O: 591 mgꢁ

/

199 mg after 1 h

2

J_{Me CH}

ꢀ

/

30 min (5.1 mmol, 5ꢁ

/

1.8 equivalents); KI: 0.22 ml (0.1

2

MHz) d (ppm): 180.5 (CO), 138.7 (C_qNCH₂Ph), 128.4,

126.9, 126.6 (C Ph), 77.3 (COH), 44.6 (NMe₂), 41.1

M, 0.022 mmol, 3 mol%); water: 20 ml; AcOEt: 20 ml;

184 mg of hydrazide 14b was obtained; yield 93%.

186

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

4.5.10. (R*,S*)-3-Hydroxy-2-methyl-pentanoic acid N-

benzyl-N?,N?-dimethyl-hydrazide (14b)

Complex 14b: colourless oil. Rf: 0.12 (eluent:

[M^ꢁꢁ

/

1Ã

/

COCHMeCOHEtÃ

/

NMe₂], 91 [C₇H₇^ꢁ], 79

[C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65 [C₅H₅^ꢁ].

CH₂Cl₂). HRMS (EI) for C₁₅H₂₄N₂O₂: [M^ꢁ] calc.:

4.5.13. Synthesis of (R*,S*)-3-hydroxy-2-methyl-

phenyl-pent-4-enoic acid N-benzyl-N?,N?-dimethyl-

hydrazide (14d)

Hydrazinocarbene complex 11d: 100 mg (0.20 mmol,

one equivalent); KH₂PO₄: 287 mg (2.10 mmol, 10.2

264.18378, found: 264.1831; [Mꢁ

found: 264.1920. ¹H-NMR (CDCl₃, 300 MHz) d (ppm):

7.4ꢂ7.1 (5H, m, CH_arom.), 4.66 (2H, d, Jꢀ15.8,

CH₂Ph), 4.58 (2H, d, Jꢀ15.8, CH₂Ph), 4.21 (1H, s

broad, OH), 3.78 (1H, ddd, J_CHOHÃCH5.5 Hz,

2.2 Hz, CHOH),

7.0 Hz, J_CHÃCHOH2.2 Hz,

CHCH₃), 2.51 (3H, s, NMe₂), 2.48 (3H, s, NMe₂), 1.7ꢂ

1.51 (1H, m, CH₂CH₃), 1.51ꢂ1.30 (1H, m, CH₂CH₃),

1.18 (3H, d, J_MeÃCHCON7.0 Hz, CHCH₃), 0.98 (3H, t,

J_{CH ÃCH}

7.5, CH₂CH₃). ¹³C-NMR DEPT (CDCl₃, 75

/

1^ꢁ] calc.: 265.19160,

/

ꢀ

/

equivalents); NaBO₃×

/4H₂O: 157 mg (1.02 mmol, five

2

J_CHOHÃCH

ꢀ

/

7.7 Hz, J_CMeHÃCHOH

ꢀ

/

equivalents); KI: 0.065 ml (0.1 M, 0.0065 mmol, 3.1

mol%); water: 6 ml; AcOEt: 6 ml; 58 mg of hydrazide

14d was obtained; yield 84%.

2

3.42 (1H, dq, J_MeÃCHCON

ꢀ

/

ꢀ

/

ꢀ

/

4.5.14. (R*,S*)-3-Hydroxy-2-methyl-phenyl-pent-4-

enoic acid N-benzyl-N?,N?-dimethyl-hydrazide (14d)

Complex 14d: colourless oil. Rf: 0.5 (eluent: MTBE).

HRMS (EI) for C₂₁H₂₆N₂O₂: [M^ꢁ] calc.: 338.1994,

found: 338.1989. ¹H-NMR (CDCl₃, 300 MHz) d (ppm):

ꢀ

/

2

3

MHz) d (ppm): 180.3 (CO), 138.6 (C_qNCH₂Ph), 128.3,

126.8, 126.7 (C Ph), 73.1 (COH), 44.5 (NMe₂), 41.0

(NCH₂Ph), 37.8 (CHCON), 26.5 (CH₂CH₃), 10.2

(NCOCHCH₃; CH₂CH₃). IR/FT (neat) n (cm^ꢃ1):

7.5ꢂ

Hz, J_trans

J_CHOHÃCHCH

4.66 (1H, ddd, J_CHOHÃCHCH

2.9 Hz, J_allylic1.5 Hz, CHOH), 4.67 (2H, d, Jꢀ

CH₂Ph), 4.61 (2H, d, Jꢀ15.8, CH₂Ph), 3.57 (1H, dq,

J_MeÃCHCON7.0 Hz, J_CMeHÃCHOH2.9 Hz, CHCH₃),

3.5ꢂ3.1 (1H, s very broad, OH), 2.53 (3H, s, NMe₂),

/

7.1 (10H, m, CH_arom.), 6.73 (1H, dd, J_allylic

16.2 Hz, CHÄCHPh), 6.23 (1H, dd,

5.2 Hz, J_transCHPh),

16.2 Hz, CH Ä

5.2 Hz, J_CMeHÃCHOH

15.8,

ꢀ1.5

/

3436 (nOH), 1630 (nCÄ

CH₃), 730 (gCH_arom.), 700 (dCH_arom.). MS (EI) m/z 265

[M^ꢁꢁ1], 264 [M^ꢁ], 221 [M^ꢁꢁ NMe₂], 203 [M^ꢁꢁ

1Ã

1ÃNMe₂Ã 1Ã

H₂O], 173 [M^ꢁÃPhCH₂], 150 [M^ꢁꢁ

COCHMeCOHEt], 149 [100%, M^ꢁÃ

COCHMeCO-

NMe₂], 91

/

O), 1497 (arCÃ/C), 1353 (dsy

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

ꢀ

/

HEt], 92 [M^ꢁꢁ

/

1Ã

/

COCHMeCOHEtÃ

/

ꢀ

/

ꢀ

/

[C₇H₇^ꢁ], 79 [C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65 [C₅H₅^ꢁ].

/

2.49 (3H, s, NMe₂), 1.25 (3H, d, J_MeÃCHCON

ꢀ7.0 Hz,

/

4.5.11. Synthesis of (R*,R*)-3-hydroxy-2-methyl-

pentanoic acid N-benzyl-N?,N?-dimethyl-hydrazide (15b)

Hydrazinocarbene complex 12b: 144 mg (0.35 mmol,

one equivalent); KH₂PO₄: 480 mg (3.53 mmol, 10.1

CHCH₃). ¹³C-NMR DEPT (CDCl₃, 75 MHz) d (ppm):

179.6 (CO), 138.7, 137.0 (C_qPh), 130.6, 129.7, 128.6,

128.5, 127.4, 127.0, 126.4 (C Phꢁ

/

CHÄ

/

CHPh), 72.7

(COH), 44.8 (NMe₂), 41.3 (NCH₂Ph), 39.9 (CHCON),

11.3 (NCOCHCH₃). IR/FT (neat) n (cm^ꢃ1): 3410

(nOH), 1954, 1889, 1810, 1733 (overtone arom.), 1631

equivalents); NaBO₃×

/

4H₂O: 276 mgꢁ96 mg after 1 h 30

/

min (2.4 mmol, 5ꢁ1.8 equivalents); KI: 0.11 ml (0.1 M,

/

0.01 mmol, 3.1 mol%); water: 10 ml; AcOEt: 10 ml; 90

mg of hydrazide 15b was obtained; yield 97.6%.

(nCÄ

(doopÄ

(dCH_arom.). MS (EI) m/z 338 [M^ꢁ], 294 [M^ꢁÃ

247 [M^ꢁÃPhCH₂], 150 [M^ꢁꢁ

1ÃCOCHMeCOHCHÄ

CHPh], 149 [100%, M^ꢁÃ

COCHMeCOHCHÄCHPh],

131 106 1Ã

[PhCHÄ

CHCO^ꢁ], [M^ꢁꢁ

NMe₂], 91 [C₇H₇^ꢁ], 79

/

O and CÄ

CH alkenyl group), 741 (gCH_arom.), 696

NMe₂],

/

C), 1495 (arCÃ

/

C), 1353 (dsy CH₃), 970

/

4.5.12. (R*,R*)-3-Hydroxy-2-methyl-pentanoic acid N-

benzyl-N?,N?-dimethyl-hydrazide (15b)

Complex 15b: colourless oil. Rf: 0.04 (eluent:

CH₂Cl₂). HRMS (EI) for C₁₅H₂₄N₂O₂: [M^ꢁ] calc.:

264.18378, found: 264.1829. ¹H-NMR (CDCl₃, 300

/

COCHMeCOHCHÄ

/

CHPhÃ

/

[C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65 [C₅H₅^ꢁ].

MHz) d (ppm): 7.4ꢂ

CH₂Ph), 3.84 (1H, s, OH), 3.6ꢂ

CHOH), 2.52 (3H, s, NMe₂), 2.49 (3H, s, NMe₂), 1.6ꢂ

1.4 (2H, m, CH₂CH₃), 1.27 (3H, d, J_MeÃCHCON7.0

Hz, CHCH₃), 1.00 (3H, t, J_{CH ÃCH}7.4, CH₂CH₃).

/

7.1 (5H, m, CH_arom.), 4.62 (2H, s,

/

3.4 (2H, m, CHMe-

4.5.15. Synthesis of (R*,S*)-3-ferrocenyl-3-hydroxy-2-

methyl-propionic acid N-benzyl-N?,N?-dimethyl-

hydrazide (14e)

Hydrazinocarbene complex 11e: 123 mg (0.21 mmol,

one equivalent); KH₂PO₄: 297 mg (2.18 mmol, 10.4

/

ꢀ

/

ꢀ

/

2

3

¹³C-NMR DEPT (CDCl₃, 75 MHz) d (ppm): 179.6

(CO), 138.8 (C_qNCH₂Ph), 128.7, 127.0, 126.8 (C Ph),

76.0 (COH), 44.8 (NMe₂), 41.2 (NCH₂Ph), 39.1

(CHCON), 29.6 (CH₂CH₃), 15.9 (NCOCHCH₃), 10.5

(CH₂CH₃). IR/FT (neat) n (cm^ꢃ1): 3436 (nOH), 1630

equivalents); NaBO₃×

/

4H₂O: 161.5 mg (1.05 mmol, five

equivalents); KI: 0.065 ml (0.1 M, 0.0065 mmol, 3.1

mol%); water: 7 ml; AcOEt: 7 ml; 80 mg of hydrazide

14e was obtained; yield 88.1%.

(nCÄ

(gCH_arom.), 699 (dCH_arom.). MS (EI) m/z 265 [M^ꢁꢁ

1], 264 [M^ꢁ], 221 [M^ꢁꢁ NMe₂], 203 [M^ꢁꢁ

1Ã 1Ã

NMe₂Ã 1ÃCOCH-

H₂O], 173 [M^ꢁÃPhCH₂], 150 [M^ꢁꢁ

MeCOHEt], 149 [100%, M^ꢁÃ

COCHMeCOHEt], 92

/

O), 1497 (arCÃ

/

C), 1353 (dsy CH₃), 728

/

4.5.16. (R*,S*)-3-Ferrocenyl-3-hydroxy-2-methyl-

propionic acid N-benzyl-N?,N?-dimethyl-hydrazide (14e)

Complex 14e: yellow oil; Rf: 0.5 (eluent: MTBE).

HRMS (EI) for C₂₃H₂₈FeN₂O₂: [M^ꢁ] calc.: 420.1500,

/

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ

/

188

187

Table 7

Crystal data and structure reﬁnement for compounds 9b, 9c, 11e and 12e

9b

9c

11e

12e

Formula

Fw

C₂₂H₂₆CrN₂O₅

450.45

C₃₁H₃₀CrN₂O₅

562.57

C₂₇H₂₈CrFeN₂O₅

568.36

C₂₇H₂₈CrFeN₂O₅

568.36

˚

Wavelength (A)

Crystal system

Space group

1.54184 (Cuꢂ

monoclinic

P2₁/n

/K_a)

0.71073 (Moꢂ

triclinic

¯

P1

/

K_a)

1.54184 (Cuꢂ

monoclinic

P2₁/c

/

K_a)

0.71073 (Moꢂ

triclinic

¯

P1

/K_a)

/

Unit cell dimensions

˚

a (A)

˚

8.509(4)

21.922 (5)

12.470(4)

18.702(5)

13.677(4)

12.215(4)

75.58(3)

87.49(3)

71.84(3)

2873(1)

4, 1.300

4.39

16.183(4)

12.236(3)

13.533(5)

12.033(4)

12.393(3)

10.630(5)

114.55(4)

110.01(3)

96.19(3)

1296(1)

b (A)

˚

c (A)

a (8)

b (8)

g (8)

93.85(2)

93.58(5)

3

˚

V (A )

2321(1)

4, 1.289

43.37

2674(1)

4, 1.412

9.87

Z, density (calc.) (Mg m^ꢃ3

)

2, 1.457

10.19

Abs. coefficient (cm^ꢃ1

)

Max. and min. transmission factor 1.000, 0.522

1.000, 0.369

1176

Smart

1176

1.000, 0.727

588

F(0 0 0)

Crystal size (mm³)

944

0.18ꢄ

4.03ꢂ69.96

/

0.32ꢄ

/

0.37

0.22ꢄ/0.21ꢄ

/0.22

0.12ꢄ

/

0.12ꢄ

/0.17

0.22ꢄ

/

0.13ꢄ

/

0.22

u range (8)

/

3.08ꢂ28.00

/

1.26ꢂ27.32

/

3.03ꢂ28.02

/

Reflns. collct., independent reflec-

tions

4590, 4393

13 827, 13 827

7330, 7330

6245, 6245

Observed reflections [I ꢀ

Data/restr./param.

/2s(I)]

2825

4393/0/282

4489

13827/0/712

3453

7330/0/305

4629

6245/0/335

Final R indices [Iꢀ

/2s(I)]

R₁ꢀ

0.2106

R₁ꢀ0.1077, wR₂ꢀ

0.2339

/

0.0792, wR₂ꢀ

/

R₁ꢀ

0.1981

R₁ꢀ0.2116, wR₂ꢀ

0.2543

/

0.0832, wR₂ꢀ

/

R₁ꢀ

0.2700

R₁ꢀ0.1939, wR₂ꢀ

0.3602

/

0.1105, wR₂ꢀ

/

R₁ꢀ

0.1262

R₁ꢀ0.0768, wR₂ꢀ

0.1401

/

0.0534, wR₂ꢀ

/

R indices (all data)

/

R₁ꢀ

/

SjjF_ojꢃ

/

jF_cjj/SjF_oj; wR₂ꢀ

/

[S[w(F_c²ꢃF²_o)²]/S[w(F²_o)²]]^1/2

.

/

1

found: 420.1512. H-NMR (CDCl₃, 300 MHz) d (ppm)

¹H-NMR (CDCl₃, 300 MHz) d (ppm): 7.4ꢂ

7.0 (5H, m,

_aromat), 4.69 (1H, d br., Jꢀ5.8 Hz, OHCHCp), 4.59

(1H, d, Jꢀ15.8 Hz, CH₂Ph), 4.50 (1H, d, Jꢀ15.8 Hz,

CH₂Ph), 4.4ꢂ4.05 (8H, m, Cp), 3.52 (1H, dq, J₁ꢀ5.8

Hz, J₂ꢀ6.9 Hz, CrCCHCH₃), 3.48 (1H, s broad, Cp),

2.44 (3H, s, NMe₂), 2.27 (3H, s, NMe₂), 1.71 (1H, s

broad, OH), 1.20 (3H, d, Jꢀ

6.9 Hz, CrCCHCH₃); ¹³C-

respectively. Crystallographic and experimental details

for the structures are summarised in Table 7.

/

H

/

The structures were solved by Patterson and Fourier

methods and refined by full-matrix least-squares proce-

dures (based on F²_o) [25] with anisotropic thermal

parameters in the last cycles of refinement for all the

non-hydrogen atoms except for the carbon atoms of the

phenyl ring in 11e. When necessary, the data correction

for the absorption was applied [26]. The hydrogen atoms

were introduced into the geometrically calculated posi-

tions and refined riding on the corresponding parent

atoms. In the final cycles of refinement, a weighting

/

NMR DEPT (CDCl₃, 75 MHz) d (ppm): 178.8 (CO),

138.8 (Cq NCH₂Ph), 128.3, 127.3, 126.8 (C Ph), 91.7

(Cq Cp), 71.3 (CHOH), 68.5, 67.9, 67.4, 65.6 (Cp), 44.7,

44.6 (NMe₂), 42.5 (CHCON), 41.2 (NCH₂Ph), 13.0

(COCHCH₃); IR/FT (neat) n (cm^ꢃ1): 3459 (nOH), 1627

scheme wꢀ

(0.1277P)²] (9c), wꢀ

[s²F²_oꢁ(0.0666)²ꢁ

1.1617P] (12e), where Pꢀ

3 was used.

/

1/[s²F²_oꢁ

/

(0.1656P)²] (9b), wꢀ

(0.2000P)²] (11e), wꢀ

(F²_oꢁ2F²_c)/

/

1/[s²F²_oꢁ

/

(nCÄ

(gCH_arom.), 701 (dCH_arom.). MS (EI) m/z 421 [M^ꢁꢁ

1], 420 [M^ꢁ], 375 [M^ꢁÃHNMe₂], 329 [M^ꢁ-PhCH₂],

149 [M^ꢁÃCOCHMeCOHFeCp₂], 149 [100%, M^ꢁÃ

/

O), 1496 (arCÃ

/

C), 1352 (dsy CH₃), 736

/

1/[s²F²_oꢁ

/

/1/

/

COCHMeCOHEt], 92 [M^ꢁꢁ

/

1Ã

/

COCHMeCOHEtÃ

/

NMe₂], 91 [C₇H₇^ꢁ], 79 [C₆H₇^ꢁ], 77 [C₆H₅^ꢁ], 65 [C₅H₅^ꢁ].

5. Supplementary material

4.5.17. X-ray data collection, structure solution and

reﬁnement for compounds 9b, 9c, 11e and 12e

The intensity data of compounds 9b, 9c, 11e and 12e

were collected at room temperature on an ENRAF

Nonius CAD 4 (9b), Philips PW 1100 (9c and 12e) and a

Bruker Smart 1000 (11e) single-crystal diffractometers,

The supplementary material for the structures in-

cludes lists of atomic coordinates for the non-H atoms,

of calculated coordinates for the hydrogen atoms, of

anisotropic thermal parameters and complete lists of

bond lengths and angles. The details of the crystal

structure investigations are deposited to the Cambridge

188

E. Licandro et al. / Journal of Organometallic Chemistry 684 (2003) 170ꢂ188

/

[7] (a) C. Jakel, K.H. Dotz, Tetrahedron 56 (2000) 2167;

(b) F. Rose-Munch, C. Le Corre-Susanne, F. Balssa, E. Rose, J.

Vaisserman, E. Licandro, A. Papagni, S. Maiorana, W. Meng,

Crystallographic Data Centre as supplementary pub-

lications Nos. CCDC-209491 (9b), CCDC-209492 (9c),

CCDC-209490 (11e), CCDC-209493 (12e). Copies of the

data can be obtained free of charge on application to

CCDC, 12 Union Road, Cambridge CB2 1EZ, UK

G.R. Stephenson, J. Organomet. Chem. 545ꢂ546 (1997) 9;

/

(c) A. Geisbauer, S. Mihan, W. Beck, J. Organomet. Chem. 501

(1995) 61;

(d) S.R. Amin, A. Sarkar, Organometallics 14 (1995) 547;

(e) R. Aumann, M. Laege, B. Krebs, Chem. Ber. 127 (1994)

731;

[Fax: ꢁ

ac.uk].

/

44-1223-336-033; e-mail: deposit@ccdc.cam.

(f) C. Kelley, M.R. Terry, A.W. Kaplan, G.L. Geoffroy, N.

Lugan, R. Mathieu, B.S. Haggerty, A.L. Rheingold, Inorg. Chim.

Acknowledgements

Acta 198ꢂ

/

200 (1992) 601ꢂ611.

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[8] C. Bouaucheau, A. Parlier, H. Rudler, J. Org. Chem. 62 (1997)

7247.

[9] W.D. Wulff, B.A. Anderson, A.J. Toole, J. Amanda, Y. Xu,

Inorg. Chim. Acta 220 (1994) 215.

The authors gratefully acknowledge joint ﬁnancial

support from the Ministero dell’Istruzione, dell’Univer-

sita` e della Ricerca Scientiﬁca (MIUR), Rome, and the

University of Milan (National project ‘‘Stereoselezione

in Sintesi Organica. Metodologie e Applicazioni’’); they

also acknowledge the CNR (Rome). The work was also

supported in the framework of an EU COST Chemistry

programme (D14/0008/99).

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30 (1989) 4061.

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Article Doi

High diastereoselective Michael and aldol additions of Fischer-type alkyl(hydrazino)carbene complexes: Synthesis of new hydrazides

DOI: 10.1016/S0022-328X(03)00523-0

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