Synthesis and characterisation of the aminocarbene complexes [η5-C5H5Fe(CO)(PPh3){=C(NHR 2)(CH2R1)}]+BF4 - [R1 = H, Me or Pr; R2 = H, Me, Et, CHMe2, CH2Ph, CH(Me)Ph, CH2CH=CH2 or CH2CH2OH]

Article abstract of DOI:10.1039/a800927i

A number of secondary aminocarbenes of the type (RS)-[(η⁵-C₅H₅)Fe(CO)(PPh ₃){=C(CH₂R¹)(NHR²)}] ⁺BF₄^- were synthesised in very good yield [66-99%, R¹ = H, Me or Pr; R² = H, Me, Et, CHMe₂, CH₂Ph, CH(Me)Ph, CH₂CH=CH₂ or CH₂CH₂OH]. The absolute configuration of one of the carbenes was established by a single-crystal X-ray diffraction experiment. The chemistry of the carbene complexes was investigated.

Full text of DOI:10.1039/a800927i

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Synthesis and characterisation of the aminocarbene complexes
[(ç5-C H )Fe(CO)(PPh ){᎐C(NHR2)(CH R1)}]؉BF [R1 ؍ H, Me
؊
᎐
5
5
3
2
4
or Pr; R2 ؍ H, Me, Et, CHMe , CH Ph, CH(Me)Ph, CH CH᎐CH
᎐
2
2
2
2
or CH2CH2OH]
Stephen G. Davies,* Alison J. Edwards, Simon Jones, Michael R. Metzler, Kazuo Yanada and
Reiko Yanada
The Dyson Perrins Laboratory, University of Oxford, South Parks Road, Oxford, UK OX1 3QY
Ϫ
A number of secondary aminocarbenes of the type (RS)-[(η5-C H )Fe(CO)(PPh ){᎐C(CH R1)(NHR2)}]ϩBF
᎐
5
5
3
2
4
were synthesised in very good yield [66–99%, R1 = H, Me or Pr; R2 = H, Me, Et, CHMe2, CH2Ph, CH(Me)Ph,
CH CH᎐CH or CH CH OH]. The absolute configuration of one of the carbenes was established by a single-
᎐
2
2
2
2
crystal X-ray diffraction experiment. The chemistry of the carbene complexes was investigated.
Previously we have established the fragment [(η5-C5H5)Fe(CO)-
R
–
(PPh3)]1–3 as a versatile chiral auxiliary for asymmetric organic
O
O
C
BF4
C
Ph2
P
Ph2
P
–
Me3O+BF4
synthesis. This iron chiral auxiliary induces high stereoselectiv-
+
Fe
Fe
ity in the reactions of a wide variety of attached ligands. For
example, deprotonation of the acyl ligand in [(η5-C5H5)Fe(CO)-
(PPh3)COCH2R] 1 generates the E-enolate (Fe trans to R) 2,
which undergoes highly stereoselective alkylation reactions
(Scheme 1). These enolate reactions require strong base (butyl-
lithium) and low temperatures (Ϫ78 ЊC). In contrast the derived
R
O
O
Me
3
1
R
methoxycarbene salt [(η5-C H )Fe(CO)(PPh ){᎐C(OMe)-
O
C
O
C
᎐
5
5
3
Ϫ
(CH2R)}]ϩBF4 34,5 may be deprotonated at ambient temper-
ature with a mild base such as methoxide to generate the
corresponding Z-enol ether (Fe cis to R) 4. Alkylation of com-
plex 4 is highly stereoselective and demethylation of the thus
formed methoxycarbene cation with iodide generates the corre-
sponding elaborated acyl complex (Scheme 1).6 The two
sequences described above are stereocomplementary given the
same face selectivity induced by the iron chiral auxiliary but
opposite enolate to enol ether geometries.
Ph2
P
Ph2
P
Fe
Fe
R
O
O
Me
–
4
2
(1) R1X
(2) I–
R1X
R1
H
H
R
O
C
O
C
Ph2
P
Ph2
P
We were interested in extending this chemistry to the nitrogen
series to see if analogous stereoselective reactions could be
achieved via α-metallated imines or enamines attached to
the iron chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3)]. Achiral
α-metallated imines attached to [Cr(CO)5] have been reported
by Hegedus et al.7 We describe here the synthesis and properties
of a range of aminocarbene cations of the type [(η5-C5H5)-
R1
R
Fe
Fe
O
O
Scheme 1
Alternatively they may be synthesised from the corresponding
acyl complexes [(η5-C5H5)Fe(CO)(PPh3)(COCH2R)] by treat-
ment with trimethyloxonium tetrafluoroborate.10 Thus O-
methylation of the iron acetyl complex [(η5-C5H5)Fe(CO)-
(PPh3)(COMe)] 5 generated the methoxycarbene derivative
Fe(CO)(PPh ){᎐C(NHR2)(CH R1)}]ϩ. Of particular relevance
᎐
3
2
to the present study is the report by Davison and Reger8 of the
reaction of racemic (RS)-[(η5-C H )Fe(CO)(PPh ){᎐C(Me)-
᎐
5
5
3
(OEt)}]ϩBF4 with (S)-(Ϫ)-α-methylbenzylamine yielding a
Ϫ
separable mixture of diastereoisomers of (R,S)-† and (S,S)-
[(η5-C H )Fe(CO)(PPh ){᎐C(Me)(OMe)}]ϩBF Ϫ 6 in 98% yield
Ϫ
.
[(η5-C H )Fe(CO)(PPh ){᎐C(Me)[NHCH(Me)Ph]}]ϩBF
᎐
5
5
3
4
᎐
5
5
3
4
(Scheme 2). Treatment of a tetrahydrofuran solution of the
methoxycarbene complex 6 at 20 ЊC with a large excess of
ammonia gas or ten molar excess of a range of primary amines
generated the corresponding aminocarbene complexes 7–13 in
high yield (Scheme 2). If a large excess of amine was not
employed then the reactions tended to be slower and the yields
were lower due to O-demethylation of 6 back to 5. Two of the
tetrafluoroborate salts 8 and 10 were converted into their
corresponding hexafluorophosphate salts 14 and 15 in excellent
Although the absolute configurations at iron for these two
diastereoisomers could not be assigned Cotton effect studies
were consistent with them being epimeric at iron as expected.
Results and Discussion
Methoxycarbene complexes [(η5-C H )Fe(CO)(PPh ){᎐C-
᎐
5
5
3
(CH2R)(OMe)}]ϩBF4 may be readily prepared by treatment
of [(η5-C5H5)Fe(CO)(PPh3)Br] with the appropriate lithium
acetylide followed by protonation to the corresponding vinyl-
idene complexes9a and subsequent addition of methanol.9b
Ϫ
Ϫ
yield by treatment with aqueous NH4ϩPF6 because of the
better solubility of the latter salts in organic solvents.
Reaction of methoxycarbene complex 6 with aniline failed to
give any of the corresponding aminocarbene complex, exclusiv-
ely regenerating the acetyl complex 5 with concomitant form-
ation of N-methylaniline. This change of reactivity may be
† The configuration at iron is given first followed by the configuration at
the α-benzylic centre.
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594
1587

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–
–
BF4
BF4
O
C
O
C
O
O
C
C
Ph2
P
Ph2
P
Ph2
P
Ph2
P
–
Me3O+BF4
+
+
–
Me3O+BF4
Fe
Fe
Fe
Fe
O
O
O
Me
OMe
6 98%
5
17 87%
16
RNH2
RNH2
7 R = H
99%
96%
95%
91%
98%
97%
88%
–
BF4
8 R = Me
–
O
C
BF4
9 R = Et
Ph2
P
O
+
10 R = CH2PH
C
Ph2
Fe
11 R = CH2CH=CH2
12 R = CH2CH2OH
13 R = CHMe2
P
+
Fe
N
R
H
N
R
H
18 R = Me
66%
70%
80%
–
–
PF6
BF4
19 R = Et
O
O
20 R = CH2Ph
C
C
Ph2
P
Ph2
–
NH4+PF6
P
+
+
Fe
Fe
–
–
BF4
PF6
N
N
R
R
O
O
C
C
Ph2
Ph2
H
H
–
NH4+PF6
P
+
P
+
Fe
Fe
8
R = Me
10 R = CH2Ph
14 R = Me
15 R = CH2Ph
96%
97%
N
CH2Ph
N
CH2Ph
H
Scheme 2
H
20
21 95%
attributed to reversible formation of the intermediate generated
by addition of the amine to the methoxycarbene in the latter
reaction with aniline but not in the former cases with primary
aliphatic amines. Consistent with the observation of Davison
and Reger,8 attempted coupling between secondary amines
(Me2NH, Et2NH or pyrrolidine) and the methoxycarbene 6
proved to be very difficult with the product mixture consisting
mostly of the demethylated neutral acetyl complex 5 and
recovered methoxycarbene 6. One aminocarbene complex
derived from a secondary amine prepared via a different route
has been reported.9b Although some resonances in the 1H NMR
spectrum of the reaction mixture were consistent with those
expected for the product aminocarbene complexes, these never
exceeded 10% of the crude reaction mixture which could not be
purified.
O-Methylation of the propanoyl complex 16 generated the
methoxycarbene 17 in 87% yield, which reacted with selected
primary amines to generate the corresponding aminocarbene
complexes 18–20 (Scheme 3). Similar reactions of the pentanoyl
complex 22 resulted, via the intermediacy of the methoxy-
carbene 23, in the formation of the aminocarbenes 24 and 25
(Scheme 3).
–
BF4
O
C
O
C
Ph2
P
Ph2
P
–
Me3O+BF4
+
Fe
Fe
O
O
Me
22
23 96%
RNH2
–
BF4
O
C
Ph2
P
+
Fe
R
N
H
24 R = Me
25 R = CH2Ph
80%
80%
Scheme 3
For comparison with the known chemistry of the iron acyl
and methoxycarbene complexes (Scheme 1), deprotonation–
electrophilic trapping experiments were performed on com-
plex 15. The following deuteriation experiments were readily
monitored by 1H NMR spectroscopy and by mass spec-
trometry. In deuteriomethanol solution containing a catalytic
amount of methoxide complete H/D exchange was observed
for the NH and CH3 protons consistent with expected inter-
mediacy under these equilibrating conditions of 26 and 27
(Scheme 4).
Under kinetically controlled deprotonation conditions
treatment of 15 with 1 equivalent of butyllithium followed by
quenching with deuteriomethanol led to the exchange of only
the NH proton and formation of 28 (Scheme 5). In the presence
of greater than 3 equivalents of butyllithium complex 15 gener-
ated, after quenching, exclusively the trideuterio derivative
30 (Scheme 5). The formation of 30 is consistent with the
intermediacy of the dilithio species 29 for which there is some
precedent in organic systems.11
Treatment of 15 with 2 equivalents of butyllithium followed
by quenching with deuteriomethanol led to a mixture of 28, 30
and 32 rather than exclusive formation of the monolithio
species 31 and hence after quenching to 32. All attempts to
isolate complex 26 were unsuccessful, only complex 15 being
recovered in each case. In all of the above experiments
attempted quenchings with methyl iodide were completely
unsuccessful indicating that the intermediates 26, 29 and 31
are unreactive towards alkylation. This observation is in direct
contrast to the reactions of the enolates 2 and enol ethers 4.
Very few methods exist for the resolution of the iron chiral
auxiliary [(η5-C5H5)Fe(CO)(PPh3)]12 and therefore we were
interested to see if any chiral recognition could be achieved
1588
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594

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–
–
O
C
BF4
O
C
PF6
Ph2
P
Ph2
P
O
C
O
C
+H+
–H+
+
Ph2
P
Ph2
P
Fe
Fe
+
Me3O+BF4
–
Fe
Fe
CH2Ph
N
CH2Ph
N
O
H
OMe
15
26
(R)-6 94%
(R)-5
+H+ –H+
Me
H
O
C
Ph
S
H2N
Ph2
P
Fe
–
BF4
N
H
CH2Ph
O
C
Ph2
P
+
27
Fe
Me
Ph
Scheme 4
N
H
O
–
PF6
C
Ph2
P
(R,S)-33 93%
+
Fe
–
BF4
N
CH2Ph
O
O
Ph2
Ph2
C
C
H
Me3O+BF4
–
P
P
+
3 BuLi
H
1 BuLi
15
Fe
Fe
O
MeO
(S)-5
(S)-6 96%
O
C
O
C
Ph2
P
Ph2
P
Li
Me
H
Fe
Fe
Ph
H2N
S
N
Li
N
CH2Ph
–
BF4
PhCH2
O
C
26
29
Ph2
P
+
CD3OD
Fe
CD3OD
Me
Ph
N
O
C
–
O
C
–
PF6
PF6
H
Ph2
P
Ph2
P
CD2H
N
+
+
(S,S)-34 95%
Fe
Fe
Scheme 6
CH2Ph
CH2Ph
N
D
D
30
28
Table 1 Selected bond distances (Å) and torsion angles (Њ) for (R,S)-33
Scheme 5
Fe(1)᎐C(1)
C(1)᎐C(2)
1.928(6) C(1)᎐N(1)
1.513(8) N(1)᎐C(3)
1.318(7)
1.495(6)
H
–
O
C
O
C
PF6
Ph2
P
Ph2
P
C(1)᎐N(1)᎐C(3)᎐C(4) Ϫ124
C(2)᎐C(1)᎐N(1)᎐C(3)
N(1)᎐C(3)᎐C(4)᎐C(5)
C(1)᎐N(1)᎐C(3)᎐C(10) 110
Fe(1)᎐C(1)᎐N(1)᎐C(3) 177
CDH2
+
H
Ϫ6
127
Fe
Fe
CH2Ph
N
N
Li
D
ation at both the iron and the α-methylbenzylamine stereogenic
centres during the conversion of the methoxycarbenes to the
aminocarbenes. Fig. 1 shows the molecular conformation of
(R,S)-33 present in the crystal structure. Selected bond lengths
and torsion angles are given in Table 1. The structure of (R,S)-
33 shows the normal pseudo-octahedral geometry around
iron with the nitrogen of the aminocarbene anti to the carbon
monoxide ligand. The α-methylbenzyl group is antiperiplanar
to the iron auxiliary with the benzylic hydrogen synperiplanar
to the aminocarbene methyl group. The conformation adopted
in the solid state parallels that of the corresponding methoxy-
carbene complex14 and is as expected on steric grounds.
PhCH2
31
32
during the reaction of the methoxycarbene complex 6 and
α-methylbenzylamine. Significant chiral recognition would
allow the kinetic resolution of racemic 6 with homochiral
α-methylbenzylamine. O-Methylation of homochiral (R)-5 gen-
erated the homochiral methoxycarbene complex (R)-6 (Scheme
6). Treatment of (R)-6 with (S)-α-methylbenzylamine generated
the corresponding aminocarbene complex (R,S)-33 as a single
diastereoisomer. Similar treatment of (S)-5 gave via (S)-613 the
aminocarbene complex epimeric at iron (S,S)-34.
The diastereoisomers (R,S)-33 and (S,S)-34 were readily dis-
tinguishable by NMR spectroscopy and their configurational
assignments were confirmed by an X-ray crystal-structure
analysis of (R,S)-33 which confirmed retention of configur-
In order to investigate the possible chiral recognition phen-
omenon, racemic methoxycarbene complex 6 was treated with
racemic α-methylbenzylamine in a variety of solvents. Employ-
ing all racemic conditions allows a direct correlation of the
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594
1589

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cm2 gϪ1. The complexes (RS)-[(η5-C5H5)Fe(CO)(PPh3)(COMe)]
(RS)-5,17 (R)-5,12 (S)-5,12 (RS)-[(η5-C5H5)Fe(CO)(PPh3)(COEt)]
(RS)-16,18 (RS)-[(η5-C5H5)Fe(CO)(PPh3)(COBu)] (RS)-22,6,19
Ϫ
(RS)-[(η5-C H )Fe(CO)(PPh ){᎐C(Me)(NHMe)}]ϩBF
(RS)-
᎐
5
5
3
4
8,20 (RS)-[(η5-C H )Fe(CO)(PPh ){᎐C(Bu)(OMe)}]ϩBF Ϫ (RS)-
᎐
5
5
3
4
2320 and (RS)-[(η5-C H )Fe(CO)(PPh ){᎐C(Bu)(NHCH -
᎐
5
5
3
2
Ϫ
Ph)}]ϩBF4 (RS)-2520 were synthesised by literature pro-
cedures. (S)-(Ϫ)-α-Methylbenzylamine was purchased from
Aldrich [α]D (neat) Ϫ39.0, this corresponds to an enantiomeric
excess of 95% {lit.,21a [α]D (neat) Ϫ40.6}. However with
the method of Parker and Taylor21b using 1H NMR with
(R)-(Ϫ)-O-acetylmandelic acid [MeCO2CH(C6H5)CO2H] an
enantiomeric excess of 99.6% was obtained.
General procedure for the synthesis of the methoxycarbenes
A nitrogen degassed solution of [(η5-C5H5)Fe(CO)(PPh3)-
(COR)] (R = Me, Et or Bu) (30 mL per 1 g of complex) was
cannulated into
a
flask containing trimethyloxonium
tetrafluoroborate (1.3 mol equivalents, dried at 60 ЊC in vacuo
for 3 h) and the resultant mixture stirred under a nitrogen
atmosphere for 8–21 h. During this time the colour of the reac-
tion mixture changed from a deep orange-red to a deep yellow-
brown. The reaction mixture was then filtered via cannula and
concentrated in vacuo to yield a yellow-brown oil which was
dissolved in a minimum amount of dichloromethane and
cannulated dropwise into diethyl ether (40 mL gϪ1) cooled to
0 ЊC, forming a bright yellow precipitate. The solvent was
removed via cannula and the residue washed twice with diethyl
ether before being dried in vacuo. For analytical analysis the
methoxycarbenes were recrystallised from the solvents
indicated.
Fig. 1 Crystal structure of (R,S)-[(η5-C5H5)Fe(CO)(PPh3){᎐C(Me)-
᎐
[NHCH(Me)Ph]}]ϩBF4Ϫ (R,S)-33
ratio of product diastereoisomers with the stereoselectivity
factor without the need to consider the complicating effects of
mass action. Unfortunately, in a range of solvents (tetrahydro-
furan, methanol, ethanol, propan-2-ol, hexane, acetone, ethyl
acetate, dibutyl ether, benzene, chloroform and carbon tetra-
chloride) equimolar mixtures of product diastereoisomers were
observed within experimental error. The complete lack of chiral
recognition does not allow a kinetic resolution procedure to be
effected. However, Davison and Reger8 have demonstrated the
classical resolution procedure by separation of (R,S)-33 and
(S,S)-34 by fractional crystallisation. Photochemical studies
on the above aminocarbene complexes have been reported
elsewhere.15
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(OMe)}]؉BF (RS)-
᎐
5
5
3
4
6. Methylation of (R,S)-5 (20.0 g, 44.1 mmol) with Me3Oϩ-
BF4Ϫ (8.46 g, 57.2 mmol) for 8 h at room temperature afforded
(RS)-6 as a yellow solid (23.99 g, 98%) which was crystallised
from CH2Cl2–Et2O as yellow microcrystals, m.p. 162–165 ЊC
(decomp.) (lit.,10a 164 ЊC); νmax 1966 (Fe᎐CO) and 1057 cmϪ1
(BF4Ϫ); δH 2.84 (3 H, s, Fe᎐CMe), 3.99 (3 H, s, Fe᎐COMe),
Experimental
All reactions and purifications were performed under a nitrogen
atmosphere using standard vacuum line and Schlenk-tube
techniques.16 All solvents were deoxygenated before use. Tetra-
hydrofuran (THF) and dichloromethane were distilled from
sodium benzophenone and calcium hydride, respectively, under
nitrogen. Analytical grade acetone (FSA) was used without
purification. Unless otherwise indicated, all commercially avail-
able reagents were used as received. Column chromatography
was performed on grade I (activated) basic alumina or on silica
gel (Merck Kieselgel 60). Elemental analyses were carried out
by the Dyson Perrins Laboratory Analytical Service. Butyl-
lithium (1.5  in hexane) and methyllithium (1.4  in diethyl
ether) were used as supplied by Aldrich. Infrared spectra were
recorded on either a Perkin-Elmer 781 or a Perkin-Elmer 1750
Fourier-transform spectrophotometer in dichloromethane solu-
tions using 1 mm NaCl cells unless otherwise stated. Proton
NMR spectra were recorded on either a Varian-Gemini 200
(200 MHz) or a Bruker AM500 (500.13 MHz) spectrometer in
CDCl3 solutions unless otherwise stated. Carbon-13, 19F and
31P NMR spectra were recorded on a Bruker AM250 spec-
trometer (at 62.90, 235.35 and 125.76 MHz respectively) in
CDCl3 solutions. Proton and 13C NMR spectra were referenced
to tetramethylsilane using internal solvent peaks. In the
Experimental section, 13C, 19F and 31P NMR data are described
in terms of the proton decoupled (broad band) spectra.
Abbreviations used: br, broad single; d, doublet; m, multiplet;
q, quartet; s, singlet; t, triplet. Mass spectra were recorded on
VG Micromass ZAB1F or MM30F instruments using FAB
techniques for organometallic compounds. Optical rotations
were recorded on a Perkin-Elmer 241 polarimeter in the sol-
vents indicated at 20 ЊC in a 1 dm cell. Concentrations (c) are
given in g 100 mLϪ1 and specific rotation in units of 10Ϫ1 deg
᎐
᎐
4.92 (5 H, d, JPH 1.2 Hz, C5H5), 7.20–7.40 (6 H, m, Ho of PPh3),
7.43–7.65 (9 H, m, H and H of PPh ); δ 44.70 (s, Fe᎐CMe),
᎐
m
p
3
C
65.24 (s, Fe᎐COMe), 87.75 (s, C H ), 129.12 (d, J 11.0, Cm
᎐
5
5
PC
of PPh3), 131.16 (s, Cp of PPh3), 132.54 (d, JPC 9.5, Co of PPh3),
132.72 (d, JPC 47.4, Cipso of PPh3), 215.47 (d, JPC 27.4, Fe᎐CO),
263.19 (d, JPC 21.4 Hz, Fe᎐C); δ 63.13; δF Ϫ154.49 and
᎐
P
Ϫ154.54 (1:3); m/z 469 (Mϩ, 87), 441 (M Ϫ CO, 86), 439 (M Ϫ
2Me, 10), 383 (439 Ϫ 2CO, 100), 318 (12), 295 (8), 263 (24),
239 (17), 183 (55), 164 (10), 108 (8), 85 (8%).
؊
(R)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(OMe)}]؉BF
4
(R)-6.
Ϫ
᎐
5
5
3
Methylation of (R)-512 (1.42 g, 3.13 mmol) with Me3OϩBF4
(0.60 g, 4.06 mmol) for 12 h at room temperature afforded (R)-6
as a yellow solid (1.64 g, 94%) which was crystallised from
CH2Cl2–Et2O as yellow microcrystals, m.p. 162–164 ЊC
(decomp.) (Found: C, 58.19; H, 4.45. C27H26BF4FeO2P requires:
C, 58.31; H, 4.72%); [α]D (20 ЊC, c = 3.2, CH2Cl2) Ϫ257.0.
؊
(S)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(OMe)}]؉BF
4
(S)-6.
Ϫ
᎐
5
5
3
Methylation of (S)-512 (2.00 g, 4.41 mmol) with Me3OϩBF4
(0.85 g, 5.73 mmol) for 12 h at room temperature afforded
(S)-611 as a yellow solid (2.35 g, 96%) which was crystallised
from CH2Cl2–Et2O as yellow microcrystals, m.p. 162–165 ЊC
(decomp.) (Found: C, 58.07; H, 4.38. C27H26BF4FeO2P requires:
C, 58.31; H, 4.72%); [α]D (20 ЊC, c = 2.3, CH2Cl2) 257.7.
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Et)(OMe)}]؉BF
4
(RS)-
᎐
5
5
3
17. Methylation of (RS)-16 (5.0 g, 10.7 mmol) with
Ϫ
Me3OϩBF4 (2.04 g, 13.9 mmol) for 21 h at room temperature
afforded (RS)-17 as a yellow solid (5.29 g, 87%) which was
1590
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594

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crystallised from CH2Cl2–Et2O as yellow microcrystals, m.p.
169–172 ЊC (decomp.) (Found: C, 58.70; H, 4.86. C28H28BF4-
FeO2P requires: C, 58.98; H, 4.95%); νmax 1966 (Fe᎐CO) and
1052 cmϪ1 (BF4Ϫ); δH 1.16 (3 H, d, J 7.6, Fe᎐CCH Me), 2.76 (2
in acetone (40 mL) at room temperature under a nitrogen
atmosphere. This resulted in the immediate precipitation of
a bright yellow solid which was filtered off and washed with
water, ethanol and diethyl ether to afford pure (RS)-14 (1.07 g,
96%) which was crystallised from CH2Cl2–Et2O as red-brown
yellow-brown plates, m.p. 172–174 ЊC (decomp.) (Found: C,
53.49; H, 4.38; N, 2.20. C28H29F6FeNOP2 requires: C, 53.61;
H, 4.66; N, 2.23%); νmax 1957 (Fe᎐CO) and 847 cmϪ1 (PF6Ϫ);
δH(CD3COCD3) 1.04 (3 H, t, J 7.3, NCH2CH3), 2.62 (3 H, s,
᎐
2
H, q, J 7.6, Fe᎐CCH Me), 4.25 (3 H, s, Fe᎐COMe), 4.89 (5 H,
᎐
᎐
2
d, JPH 1.4 Hz, C5H5), 7.20–7.40 (6 H, m, Ho of PPh3), 7.45–7.60
(9 H, m, H and H of PPh ); δ 10.17 (s, Fe᎐CCH Me), 49.75
᎐
m
p
3
C
2
(s, Fe᎐CCH Me), 65.84 (s, Fe᎐COMe), 87.31 (s, C H ), 129.15
᎐
᎐
2
5
5
(d, JPC 9.9, Cm of PPh3), 131.41 (s, Cp of PPh3), 132.75 (d, JPC
10.4, Co of PPh3), 132.84 (d, JPC 47.3, Cipso of PPh3), 216.26 (d,
Fe᎐CMe), 3.52 (1 H, dq, J 13.2, 7.0, NCH CH ), 3.59 (1 H, dq,
᎐
2
3
JPC 26.8, Fe᎐CO), 257.91 (d, JPC 21.1 Hz, Fe᎐C); δ 62.28; δ
J 13.3, 7.1, NCH2CH3), 4.98 (5 H, s, C5H5), 7.38 (6 H, dd, JPH
10.3, JHH 7.3 Hz, Ho of PPh3), 7.56–7.63 (9 H, m, Hm and Hp of
PPh3), 9.79 (1 H, br s, NHEt); δC(CD3COCD3) 13.60 (s,
᎐
P
F
Ϫ154.69 and Ϫ154.75 (1:3); m/z 483 (Mϩ, 100), 455 (M Ϫ CO,
86), 439 (M Ϫ Me Ϫ Et, 14), 383 (M Ϫ Me Ϫ Et, 100), 318 (18),
295 (38), 263 (36), 239 (19), 221 (16), 193 (38), 183 (65), 161 (24),
121 (31), 103 (12), 85 (25%).
NCH CH ), 37.52 (s, Fe᎐CMe), 49.57 (s, NCH CH ), 86.46 (s,
᎐
2
3
2
3
C5H5), 129.99 (d, JPC 9.9, Cm of PPh3), 131.94 (s, Cp of PPh3),
133.79 (d, JPC 9.9, Co of PPh3), 133.37 (d, JPC 45.5, Cipso of
PPh3), 218.67 (d, JPC 29.3, Fe᎐CO), 266.67 (d, JPC 22.1 Hz,
General procedure for the synthesis of the aminocarbenes
Fe᎐C); δ (CD COCD ) 73.12, Ϫ142.92 (septet, J 708.5 Hz,
᎐
P
3
3
PF
The amine (10 mol equivalents) was injected dropwise into a
solution of the methoxycarbene in THF (20 mL gϪ1) under a
nitrogen atmosphere and the resultant red-orange solution
stirred at the specified temperatures for the times indicated. The
reaction mixture was then concentrated in vacuo to yield a red
oil which was dissolved in a minimum amount of dichloro-
methane and cannulated dropwise into diethyl ether (40 mL
PF6Ϫ); δF(CD3COCD3) Ϫ67.48 (d, JPF 708.5 Hz, PF6Ϫ); m/z 482
(Mϩ, 65), 454 (M Ϫ CO, 34), 383 (10), 318 (10), 263 (14), 192
(100), 183 (20), 121 (18), 70 (20%).
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHCH Ph)}]؉BF
᎐
5
5
3
2
4
(RS)-10. Reaction of (RS)-6 (24.27 g, 44.0 mmol) with benzyl-
amine (42.6 mL, 0.43 mol) at 0 ЊC for 2 h afforded (RS)-10 as
a yellow solid (25.12 g, 91%). Recrystallisation from CH2Cl2–
EtOH gave yellow microneedles, m.p. 199–201 ЊC (decomp.)
[lit.,9b 203 ЊC (decomp.)] (Found: C, 63.08; H, 4.92; N, 2.23; P,
4.96. C33H31BF4FeNOP requires: C, 62.79; H, 4.95; N, 2.22; P,
4.91%); νmax 1960 (Fe᎐CO) and 1062 cmϪ1 (BF4Ϫ); δH(CDCl3)
g
Ϫ1) cooled to 0 ЊC forming a bright yellow precipitate. The
solvent was removed via cannula and the residue washed twice
with diethyl ether before being dried in vacuo. For analytical
analysis the aminocarbenes were recrystallised from the
solvents indicated.
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NH )}]؉BF
(RS)-
2.40 (3 H, s, Fe᎐CMe), 4.66 (1 H, dd, J 14.4, 6.8, NCH Ph),
᎐
2
᎐
5
5
3
2
4
4.76 (1 H, dd, J 14.4, 5.5, NCH2Ph), 4.90 (5 H, d, JPH 1.6,
C5H5), 7.02 (2 H, br d, J 7.0, Ho of Ph), 7.11 (6 H, dd, JPH 10.9,
JHH 7.7, Ho of PPh3), 7.20–7.29 (3 H, m, Hm and Hp of Ph), 7.40
(6 H, td, J 7.4, 2.0, Hm of PPh3), 7.48 (3 H, td, J 7.9, 2.0 Hz, Hp
of PPh3), 10.14 (1 H, br s, NHCH2Ph); δH(CD3COCD3) 2.67
7. Reaction of (RS)-6 (0.91 g, 1.64 mmol) with gaseous NH3
for 1.5 h at room temperature afforded (RS)-7 as a yellow solid
(0.87 g, 99%) which was crystallised from CH2Cl2–Et2O as
yellow microneedles, m.p. 93–97 ЊC (decomp.) (Found: C,
57.89; H, 4.85; N, 2.62; P, 5.57. C26H25BF4FeNOPؒ0.67 C2H10O
requires: C, 57.87; H, 4.86; N, 2.53; P, 5.60%); νmax 1958
(Fe᎐CO) and 1098 cmϪ1 (BF4Ϫ); δ 2.40 (3 H, s, Fe᎐CMe), 4.76
(3 H, s, Fe᎐CMe), 4.74 (1 H, d, J 13.2, NCH Ph), 4.82 (1 H, d,
᎐
2
J 13.3, NCH2Ph), 5.02 (5 H, d, JPH 0.9, C5H5), 7.20 (2 H, dd,
J 7.5, 2.1, Ho of Ph), 7.30 (6 H, dd, JPH 10.7, JHH 7.8, Ho of
PPh3), 7.35–7.40 (3 H, m, Hm and Hp of Ph), 7.50 (6 H, td, J 7.7,
2.0, Hm of PPh3), 7.58 (3 H, td, J 7.2, 1.8 Hz, Hp of PPh3), 10.32
᎐
H
(5 H, d, JPH 1.2 Hz, C5H5), 7.30–7.33 (6 H, m, Ho of PPh3),
7.50–7.53 (9 H, m, Hm and Hp of PPh3), 9.26 (1 H, br s, NH2),
9.37 (1 H, br s, NH2); δC 43.75 (s, Fe᎐CMe), 85.65 (s, C H ),
᎐
5
5
(1 H, br s, NHCH Ph); δ (CD COCD ) 37.47 (s, Fe᎐CMe),
᎐
2
C
3
3
129.16 (d, JPC 10.2, Cm of PPh3), 131.17 (s, Cp of PPh3), 132.78
(d, JPC 9.4, Co of PPh3), 133.03 (d, JPC 44.7, Cipso of PPh3),
52.49 (s, NCH2Ph), 85.57 (s, C5H5), 127.69 (s, Cp of Ph), 127.89
(s, Cm of Ph), 128.76 (s, Co of Ph), 128.91 (d, JPC 9.2, Cm of
PPh3), 130.83 (s, Cp of PPh3), 132.53 (d, JPC 9.7, Co of PPh3),
133.25 (d, JPC 44.4, Cipso of PPh3), 135.45 (s, Cipso of Ph),
217.38 (d, JPC 28.1, Fe᎐CO), 273.89 (d, JPC 19.4 Hz, Fe᎐C); δ
᎐
P
66.46; δF Ϫ153.06 and Ϫ153.11 (1:3); m/z 454 (Mϩ, 100),
426 (M Ϫ CO, 58), 383 (24), 295 (30), 263 (42), 183 (35), 164
(82), 121 (18), 85 (18%).
217.85 (d, JPC 28.8, Fe᎐CO), 265.44 (d, JPC 23.9 Hz, Fe᎐C);
᎐
δP(CD3COCD3) 67.31; δF(CD3COCD3) Ϫ153.42 and Ϫ153.48
(1:3); m/z 544 (Mϩ, 37), 516 (M Ϫ CO, 7), 383 (7), 295 (9),
254 (38), 152 (47), 135 (42), 103 (34), 85 (95), 59 (70), 47 (100%).
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHEt)}]؉BF ؊ (RS)-
᎐
5
5
3
4
9. Reaction of (RS)-6 (1.00 g, 1.80 mmol) with gaseous ethyl-
amine for 2 h at room temperature afforded (RS)-9 as a yellow
solid (0.97 g, 95%) which was crystallised from CH2Cl2–
Et2O as red-brown-yellow microcrystals, m.p. 184–187 ЊC
(decomp.) (Found: C, 58.86; H, 5.09; N, 2.34; P, 5.57.
C28H29BF4FeNOP requires: C, 59.09; H, 5.14; N, 2.46; P,
5.44%); νmax 1954 (Fe᎐CO) and 1056 cmϪ1 (BF4Ϫ); δH 0.93 (3 H,
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHCH Ph)}]؉PF
᎐
5
5
3
2
6
(RS)-15. A saturated solution of NH4PF6 in water (150 mL)
was added dropwise to a solution of (RS)-10 (1.00 g, 1.58
mmol) in acetone (200 mL) at room temperature under a nitro-
gen atmosphere. This resulted in the immediate precipitation of
a bright yellow solid which was filtered off, washed with water,
ethanol and diethyl ether to afford pure (RS)-15 (1.06 g, 97%).
Recrystallisation from CH2Cl2–acetone gave yellow micro-
needles, m.p. 190–192 ЊC (Found: C, 57.34; H, 4.32; N, 2.06.
C33H31F6FeNOP2 requires: C, 57.49; H, 4.54; N, 2.03%); νmax
1959 (Fe᎐CO) and 841 cmϪ1 (PF6Ϫ); δH(CD3COCD3) 2.69 (3 H,
d, J 3.0, Fe᎐CMe), 4.73 (1 H, dd, J 14.8, 3.8, NHCH Ph), 4.83
t, J 7.1, NCH CH ), 2.39 (3 H, s, Fe᎐CMe), 3.45 (2 H, m,
᎐
2
3
NCH2CH3), 4.77 (5 H, d, JPH 1.1 Hz, C5H5), 7.20–7.30 (6 H, m,
Ho of PPh3), 7.40–7.50 (9 H, m, Hm and Hp of PPh3), 9.57 (1 H,
br s, NHEt); δ 13.20 (s, NCH CH ), 36.92 (s, Fe᎐CMe), 44.88
᎐
C
2
3
(s, NCH2CH3), 85.33 (s, C5H5), 129.05 (d, JPC 9.8, Cm of PPh3),
131.01 (s, Cp of PPh3), 132.69 (d, JPC 9.2, Co of PPh3), 133.19
(d, JPC 45.1, Cipso of PPh3), 217.66 (d, JPC 28.8, Fe᎐CO), 263.69
᎐
2
(1 H, dd, J 14.8, 5.3, NHCH2Ph), 5.02 (5 H, d, JPH 1.5, C5H5),
7.20 (2 H, dd, J 7.6, 2.0, Ho of Ph), 7.30 (6 H, dd, JPH 10.8, JHH
7.7, Ho of PPh3), 7.35–7.42 (3 H, m, Hm and Hp of Ph), 7.50
(6 H, td, J 7.9, 2.3, Hm of PPh3), 7.60 (3 H, tq, J 7.8, 1.9 Hz, Hp
of PPh3), 10.26 (1 H, br s, NHCH2Ph); δC(CD3COCD3) 38.29
(d, JPC 21.0 Hz, Fe᎐C); δ 67.65; δ Ϫ153.80 and Ϫ153.85 (1:3);
᎐
P
F
m/z 482 (Mϩ, 73), 454 (M Ϫ CO, 28), 383 (9), 318 (10), 295 (8),
263 (14), 192 (100%).
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHMe)}]؉PF
᎐
5
5
3
6
(RS)-14. A saturated solution of NH4PF6 in water (150 mL)
was added dropwise to a solution of (RS)-8 (1.01 g, 1.78 mmol)
(s, Fe᎐CMe), 54.14 (s, NCH Ph), 86.36 (s, C H ), 129.00 (s, C
᎐
2 5 5 p
of Ph), 129.19 (s, Cm of Ph), 129.88 (s, Co of Ph), 129.91 (d, JPC
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594
1591

View Article Online
8.3, Cm of PPh3), 131.90 (s, Cp of PPh3), 133.50 (d, JPC 9.6, Co
of PPh3), 133.67 (d, JPC 31.4, Cipso of PPh3), 134.17 (s, Cipso of
(R,S)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)[NHCH(Me)Ph]}]؉-
᎐
5 5 3
BF4؊ (R,S)-33. Reaction of (R)-6 (0.40 g, 0.72 mmol) with (S)-
α-methylbenzylamine (0.93 mL, 7.19 mmol) at room temper-
ature for 2 h afforded (R,S)-33 as a yellow solid (0.43 g, 93%).
Recrystallisation from CH2Cl2–EtOH gave orange micro-
needles, m.p. 194–196 ЊC (decomp.) [lit.,8 195 ЊC (decomp.)]
(Found: C, 63.51; H, 5.16; N, 2.16; P, 5.00. C34H33BF4FeNOP
requires: C, 63.29; H, 5.15; N, 2.17; P, 4.80%); [α]D (20 ЊC,
c = 3.00, CH2Cl2) Ϫ16.3; νmax 1965 (Fe᎐CO) and 1058 cmϪ1
(BF4Ϫ); δH(CD3COCD3) 1.60 [3 H, d, J 6.8 Hz, NHCH-
Ph), 218.85 (d, JPC 30.8, Fe᎐CO), 271.44 (d, JPC 23.1 Hz, Fe᎐C);
᎐
δP(CD3COCD3) 67.49 (s, PPh3), Ϫ147.12 (septet, JPF 706.5 Hz,
PF6Ϫ); δF(CD3COCD3) Ϫ69.18 (d, JPF 707.7 Hz, PF6Ϫ); m/z
544 (Mϩ, 85), 516 (M Ϫ CO, 13), 383 (14), 279 (19), 254 (100),
212 (14), 183 (20), 91 (20), 85 (24), 59 (18), 47 (27%).
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHCH CH᎐
᎐
᎐
5
5
3
2
؊
CH2)}]؉BF4 (RS)-11. Reaction of (RS)-6 (0.50 g, 0.90 mmol)
with allylamine (1.18 g, 20 mmol) at room temperature for 2 h
afforded (RS)-11 as a yellow solid (0.51 g, 98%). Recrystallis-
ation from CH2Cl2–EtO2 gave red microneedles, m.p. 174–
177 ЊC (Found: C, 59.77; H, 4.86; N, 1.97; P, 5.18. C29H29-
BF4FeNOP requires: C, 59.93; H, 5.03; N, 2.41; P, 5.33%);
νmax 1955 (Fe᎐CO) and 1055 cmϪ1 (BF4Ϫ); δH 2.37 (3 H, s,
(Me)Ph], 2.64 (3 H, Fe᎐CMe), 5.01 (5 H, d, JPH 1.3, C5H5), 5.27
᎐
[1 H, quintet, J 6.8 Hz, NHCH(Me)Ph], 7.17–7.63 (20 H, m,
PPh3 and Ph), 9.98 [1 H, br s, NHCH(Me)Ph]; δH(CDCl3) 1.54
[3 H, d, J 6.8, NHCH(Me)Ph], 2.52 (3 H, s, Fe᎐CMe), 4.84
᎐
(5 H, d, JPH 1.3 Hz, C5H5), 5.00 [1 H, quintet, J 6.8, NHCH-
(Me)Ph], 6.89–7.53 (20 H, m, PPh3 and Ph), 9.46 [1 H, br s,
NHCH(Me)Ph]; δC(CDCl3) 22.11 [s, NHCH(Me)Ph], 39.12
Fe᎐CMe), 4.00–4.10 (2 H, m, NCH CH᎐CH ), 4.78 (5 H, s,
᎐
᎐
2
2
C H ), 5.08 (1 H, d, J 12.5, NCH CH᎐CH ), 5.11 (1 H, d, J 4.5
(s, Fe᎐CMe), 60.64 [s, NHCH(Me)Ph], 85.60 (s, C H ), 126.72
᎐
5 5
᎐
5
5
2
2
Hz, NCH CH᎐CH ), 5.43–5.52 (1 H, m, NCH CH᎐CH ),
(s, Cm of Ph), 128.1 (s, Cp of Ph), 129.1 (s, Co of Ph), 129.25 (d,
JPC 9.8 Hz, Cm of PPh3), 131.18 (s, Cp of PPh3), 132.74 (d, JPC
9.7, Co of PPh3), 133.17 (d, JPC 44.8, Cipso of PPh3), 140.38 (s,
Cipso of Ph), 217.53 (d, JPC 29.8, Fe᎐CO), 267.03 (d, JPC 21.9 Hz,
᎐
᎐
2
2
2
2
7.24–7.27 (6 H, m, Ho of PPh3), 7.48–7.50 (9 H, m, Hm and Hp
of PPh ), 9.78 (1 H, br s, NHCH CH᎐CH ); δ 37.46 (s,
᎐
3
2
2
C
Fe᎐CMe), 52.44 (s, NCH CH᎐CH ), 85.58 (s, C H ), 119.95 (s,
᎐
᎐
2
2
5
5
NCH CH᎐CH ), 129.14 (d, J 9.5, Cm of PPh3), 130.67 (s,
Fe᎐C); δ (CDCl ) 68.84; δ (CDCl ) Ϫ153.07 and Ϫ153.13
᎐
P 3 F 3
᎐
2
2
PC
NCH CH᎐CH ), 131.09 (s, C of PPh ), 132.80 (d, J 9.5, Co
(1:3); m/z 558 (Mϩ, 71), 530 (M Ϫ CO, 92), 383 (8), 268 (100),
239 (9), 226 (14), 203 (13), 183 (32), 162 (20), 146 (13), 121 (20),
105 (49%).
᎐
2
2
p
3
PC
of PPh3), 133.26 (d, JPC 45.7, Cipso of PPh3), 217.80 (d, JPC 29.0,
Fe᎐CO), 265.96 (d, JPC 22.6 Hz, Fe᎐C); δ 67.05; δ Ϫ153.77
᎐
P
F
and Ϫ153.83 (1:3); m/z 494 (Mϩ, 100), 466 (M Ϫ CO, 22),
458 (9), 383 (20), 310 (12), 295 (18), 263 (30), 239 (11), 227 (17),
204 (87), 183 (37), 162 (20), 121 (18%).
(S,S)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)[NHCH(Me)Ph]}]؉-
᎐
5
5
3
BF4؊ (S,S)-34. Reaction of (S)-6 (0.40 g, 0.72 mmol) with (S)-
α-methylbenzylamine (0.93 mL, 7.19 mmol) at room temper-
ature for 2 h afforded (S,S)-34 as a yellow solid (0.46 g, 95%).
Recrystallisation from CH2Cl2–EtOH gave yellow plates, m.p.
194–196 ЊC (decomp.) [lit.,8 m.p. 186 ЊC (decomp.)] (Found: C,
63.42; H, 5.18; N, 2.08; P, 5.03. C34H33BF4FeNOP requires: C,
63.29; H, 5.15; N, 22.17; P, 4.80%); [α]D (20 ЊC, c = 1.005,
CH2Cl2) 154.6; νmax 1965 (Fe᎐CO) and 1062 cmϪ1 (BF4Ϫ);
δH(CD3COCD3) 1.41 [3 H, d, J 6.8, NHCH(Me)Ph], 2.72 (3 H,
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHCH CH OH)}]؉-
᎐
5
5
3
2
2
BF4؊ (RS)-12. Reaction of (RS)-6 (1.80 g, 3.24 mmol) with
aminoethanol (1.95 mL, 32.4 mmol) at room temperature
for 15 min afforded (RS)-12 as an orange solid (2.08 g, 97%).
Recrystallisation from CH2Cl2–EtO2 gave orange microneedles,
m.p. 139–141 ЊC (Found: C, 59.64; H, 5.18; N, 2.23; P, 5.05.
C28H29BF4FeNO2P requires: C, 59.52; H, 5.00; N, 2.39; P,
5.29%); νmax 1940 (Fe᎐CO) and 1057 cmϪ1 (BF4Ϫ); δH 2.46 (3 H,
Fe᎐CMe), 4.97 (5 H, d, JPH 1.4, C5H5), 5.32 [1 H, quintet, J 6.8
᎐
s, Fe᎐CMe), 2.81 (1 H, t, J 5.5, NCH CH OH), 3.42–3.58 (3 H,
Hz, NHCH(Me)Ph], 7.29–7.61 (20 H, m, PPh3 and Ph), 9.90 [1
H, br s, NHCH(Me)Ph]; δH(CDCl3) 1.40 [3 H, d, J 6.9,
᎐
2
2
m, NCH2CH2OH), 4.77 (5 H, d, JPH 1.0, C5H5), 7.28 (6 H, dd,
JPH 10.9, JHH 7.5, Ho of PPh3), 7.50 (6 H, td, J 6.9, 1.9, Hm of
PPh3), 7.55 (3 H, td, J 7.5, 2.0 Hz, Hp of PPh3), 9.35 (1 H, br s,
NHCH(Me)Ph], 2.48 (3 H, s, Fe᎐CMe), 4.76 (5 H, d, J 1.3,
᎐
PH
C5H5), 4.79 [1 H, quintet, J 6.9 Hz, NHCH(Me)Ph], 7.18–7.53
(20 H, m, PPh3 and Ph), 9.68 [1 H, br s, NHCH(Me)Ph];
NHCH2CH2OH); δC 38.11 (s, Fe᎐CMe), 52.10 (s, NCH -
᎐
2
CH2OH), 59.83 (s, NCH2CH2OH), 85.97 (s, C5H5), 129.68 (d,
JPC 9.6 Hz, Cm of PPh3), 131.70 (s, Cp of PPh3), 133.37 (d, JPC
10.0, Co of PPh3), 133.74 (d, JPC 53.9, Cipso of PPh3), 218.25 (d,
δC 21.61 [s, NHCH(Me)Ph], 38.83 (s, Fe᎐CMe), 60.65 [s,
᎐
NHCH(Me)Ph], 85.30 (s, C5H5), 126.51 (s, Cm of Ph), 128.1 (s,
Cp of Ph), 129.1 (s, Co of Ph), 129.25 (d, JPC 9.8, Cm of PPh3),
131.18 (s, Cp of PPh3), 132.74 (d, JPC 9.7 Hz, Co of PPh3), 133.08
(d, JPC 44.8, Cipso of PPh3), 140.60 (s, Cipso of Ph), 217.33 (d, JPC
JPC 28.4, Fe᎐CO), 267.64 (d, JPC 22.1 Hz, Fe᎐C); δ 69.52;
᎐
P
δF Ϫ153.54 and Ϫ153.58 (1:3); m/z 498 (Mϩ, 71), 470 (M Ϫ CO,
8), 383 (13), 318 (6), 295 (35), 263 (25), 208 (100), 183 (22),
142 (13%).
29.8, Fe᎐CO), 267.93 (d, JPC 21.9 Hz, Fe᎐C); δ (CDCl )
᎐
P
3
68.85; δF(CDCl3) Ϫ153.07 and Ϫ153.13 (1:3); m/z 558 (Mϩ,
60), 530 (M Ϫ CO, 13), 383 (8), 268 (100), 239 (9), 226 (12),
183 (19), 163 (19), 105 (20), 89 (23), 77 (35), 59 (85%).
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)(NHCHMe )}]؉BF
᎐
5
5
3
2
4
(RS)-13. Reaction of (RS)-6 (1.11 g, 2.00 mmol) with isopro-
pylamine (1.18 g, 20 mmol) at room temperature for 2 h
afforded (RS)-13 as a yellow solid (1.02 g, 88%). Recrystallis-
ation from CH2Cl2–EtOH gave yellow microcrystals, m.p. 213–
214 ЊC (decomp.) (Found: C, 59.81; H, 5.58; N, 2.29; P, 5.15.
C29H31BF4FeNOP requires: C, 59.73; H, 5.35; N, 2.40; P,
5.31%); νmax 1964 (Fe᎐CO) and 1058 cmϪ1 (BF4Ϫ); δH 0.97 (3 H,
d, J 6.5, CHMe2), 1.23 (3 H, d, J 6.5, CHMe2), 2.53 (3 H, s,
(RS,SR)- and (RR,SS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)-
᎐
5
5
3
[NHCH(Me)Ph]}]؉BF4 (RS,SR)-33 and (RR,SS)-34. A solu-
tion of ( )-α-methylbenzylamine (4.85 g, 40 mmol) in THF (20
mL) was added to (RS)-6 (1.11 g, 2.0 mmol) and the reaction
mixture was stirred for 2 h at 0 ЊC under nitrogen. The yellow
precipitate that had formed in the reaction mixture was filtered
off, washed with THF, and dried in vacuo. The precipitate [0.77
g, 60%, (RS,SR):(RR,SS) = 92:8] was recrystallised twice from
CH2Cl2–EtOH to give yellow needles (RS,SR) (0.66 g, 51%).
The filtrate and washings were combined and concentrated in
vacuo. The residual oil was distilled at 60–65 ЊC under vacuum
to give ( )-α-methylbenzylamine as a colourless oil (2.30 g,
47%) and a yellow residue which was left overnight to crystal-
lise. Filtration followed by washing with benzene gave a yellow
solid which consisted (1H NMR spectroscopy) of (RS,SR):
(RR,SS) in a ratio of 15:85. Column chromatography on alu-
mina (5% MeOH–CH2Cl2) followed by two crystallisations
؊
Fe᎐CMe), 3.96 (1 H, octet, NHCHMe ), 4.80 (5 H, s, C H ),
᎐
2
5
5
7.19–7.27 (6 H, m, Ho of PPh3), 7.48–7.53 (9 H, m, Hm and Hp
of PPh3), 9.22 (1 H, br s, NHCHMe2); δC 20.67 (s, NHCHMe2),
21.21 (s, NHCHMe2), 37.38 (s, Fe᎐CMe), 52.51 (s,
᎐
NHCHMe2), 85.40 (s, C5H5), 129.25 (d, JPC 9.8, Cm of PPh3),
131.18 (s, Cp of PPh3), 132.74 (d, JPC 9.7, Co of PPh3), 133.07 (d,
JPC 44.8 Hz, Cipso of PPh3), 217.54 (d, JPC 28.8, Fe᎐CO), 262.48
(d, JPC 21.8 Hz, Fe᎐C); δ 68.32; δ Ϫ152.73 and Ϫ152.79 (1:3);
᎐
P
F
m/z 496 (Mϩ, 35), 468 (M Ϫ CO, 15), 383 (6), 318 (10), 294 (9),
206 (100), 183 (27), 164 (20), 121 (21), 84 (25), 56 (9%).
1592
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594

View Article Online
from CH2Cl2–benzene gave the (RR,SS) diastereoisomers as
yellow needles (0.139 g, 11%).
267.04 (d, JPC 23.2 Hz, Fe᎐C); δ 67.19; δF Ϫ153.57 and
᎐
P
Ϫ153.63 (1:3); m/z 496 (Mϩ, 73), 468 (M Ϫ CO, 21), 383 (12),
318 (10), 295 (10), 279 (32), 263 (13), 206 (100), 183 (17), 129
(40), 84 (27%).
(R,S)- and (S,S)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)[NHCH-
᎐
A
5
5
3
؊
(Me)Ph]؉BF4
(R,S)-33 and (S,S)-34.
solution of
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Et)(NHCH Ph)}]؉BF
(S)-(Ϫ)-α-methylbenzylamine (5.69 g, 47 mmol) in THF (47
mL) was added to (RS)-6 (2.64 g, 4.7 mmol) and the reaction
mixture was stirred for 2.75 h at 0 ЊC. The red reaction mixture
was concentrated to about 30 mL and was then stirred for a
further 1.5 h during which time a precipitate formed. The
yellow precipitate was filtered off, washed with THF and dried
in vacuo. The precipitate (1.14 g, 1.77 mmol, 38%) was shown to
consist of a mixture of diastereoisomers of (R,S):(S,S) in the
ratio of 93:7. This solid was recrystallised from EtOH (150
mL) to give pure (R,S)-33 as yellow needles (0.95 g, 1.48 mmol,
31%). The filtrate and washings were combined and concen-
trated in vacuo. The residual oil was distilled at 60–65 ЊC in
vacuo to give (S)-(Ϫ)-α-methylbenzylamine as a colourless oil
{4.32 g, 76%, [α]D (neat) Ϫ39.4Њ}. The resultant residue was dis-
solved in a minimum amount of benzene and left to crystallise
over 3 d. Filtration followed by washing with benzene gave a
mixture of (R,S):(S,S) in the ratio of 22:78. Two recrystallis-
ations from EtOH gave pure (S,S)-34 as yellow plates (0.44 g,
0.68 mmol, 15%).
᎐
5
5
3
2
4
(RS)-20. Reaction of (RS)-17 (7.29 g, 0.13 mol) with benzyl-
amine (14.2 mL, 0.13 mol) at 0 ЊC for 2 h afforded (RS)-20
as a yellow solid (6.73 g, 80%). Recrystallisation from CH2Cl2–
EtOH gave yellow microneedles, m.p. 197–199 ЊC (decomp.)
(Found: C, 63.15; H, 4.91; N, 2.05; P, 4.74. C34H33BF4FeNOP
requires: C, 63.15; H, 5.16; N, 2.17; P, 4.80%); νmax 1957
(Fe᎐CO) and 1068 cmϪ1 (BF4Ϫ); δH 1.09 (3 H, t, J 7.6, Fe᎐
᎐
CCH CH ), 2.41–2.06 (1 H, m, Fe᎐CCH CH ), 2.71–2.74 (1 H,
᎐
2
3
2
3
m, Fe᎐CCH CH ), 4.40 (1 H, dd, J 14.2, 7.4, NCH Ph), 4.84
᎐
2
3
2
(1 H, dd, J 14.2, 4.5, NCH2Ph), 4.90 (5 H, d, JPH 1.6, C5H5),
6.95 (2 H, d, J 7.3, Ho of Ph), 7.08 (6 H, dd, JPH 10.1, JHH 7.5,
Ho of PPh3), 7.09 (3 H, br d, J 8.1, Hm of PPh3), 7.15 (2 H, br t,
J 7.5, Hm of Ph), 7.21 (1 H, t, J 7.5, Hp of Ph), 7.38 (6 H, br t,
J 7.4, Hm of PPh3), 7.47 (3 H, br t, J 7.9 Hz, Hp of PPh3), 10.19
(1 H, br s, NHCH2Ph); δC 10.94 (s, Fe᎐CCH CH ), 41.68 (s,
᎐
2
3
Fe᎐CCH CH ), 52.08 (s, NCH Ph), 85.74 (s, C H ), 128.32 (s,
᎐
2
3
2
5
5
Cp of Ph), 128.69 (s, Cm of Ph), 129.49 (s, Co of Ph), 129.59 (d,
JPC 9.7, Cm of PPh3), 131.59 (s, Cp of PPh3), 133.26 (d, JPC 9.7,
Co of PPh3), 133.47 (d, JPC 45.6, Cipso of PPh3), 136.75 (s, Cipso of
Ph), 218.40 (d, JPC 29.8, Fe᎐CO), 268.45 (d, JPC 23.9 Hz, Fe᎐C);
᎐
Coupling reactions with secondary amines and amino acid
derivatives
δP 67.33; δF Ϫ153.01 and Ϫ153.06 (1:3); m/z 558 (Mϩ, 74),
530 (M Ϫ CO, 7), 383 (11), 318 (8), 295 (10), 268 (100), 212 (17),
183 (20), 91 (30), 85 (22), 47 (17%).
Attempted coupling reactions of (RS)-6 with Me2NH, Et2NH,
pyrrolidine, glycine, glycine methyl ester, and glycine tert-butyl
ester under the standard reaction conditions afforded mostly
unreacted starting material and demethylated (RS)-5.
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Et)(NHCH Ph)}]؉PF
᎐
5
5
3
2
6
(RS)-21. A saturated solution of NH4PF6 in water (80 mL) was
added dropwise to a solution of (RS)-20 (1.00 g, 1.55 mmol) in
acetone (120 mL) at room temperature under a nitrogen atmos-
phere. This resulted in the immediate precipitation of a bright
yellow solid which was filtered off, washed with water, ethanol
and diethyl ether to afford pure (RS)-21 (1.04 g, 95%).
Recrystallisation from CH2Cl2–acetone gave yellow micro-
needles, m.p. 186–188 ЊC (Found: C, 58.29; H, 4.72; N, 2.06.
C34H33F6FeNOP2 requires: C, 58.05; H, 4.73; N, 1.99%); νmax
1958 (Fe᎐CO) and 842 cmϪ1 (PF6Ϫ); δH(CD3COCD3) 1.21 (3 H,
t, J 7.7, Fe᎐CCH CH ), 2.36–2.42 (1 H, m, Fe᎐CCH CH ),
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Et)(NHMe)}]؉BF
؊
᎐
5
5
3
4
(RS)-18. Reaction of (RS)-17 (1.32 g, 2.37 mmol) with
aqueous MeNH2 (40%, 1.86 mL, 23.7 mmol) for 2 h at 0 ЊC
afforded (RS)-18 as a yellow solid (0.89 g, 66%) which was
crystallised from CH2Cl2–Et2O as yellow rods (hemisolvate),
m.p. 185–189 ЊC (decomp.) (Found: C, 59.27; H, 5.45; N, 2.31.
C28H29BF4FeNOPؒ0.5C4H10O requires: C, 59.44; H, 5.66; N,
2.31%); νmax 1953 (Fe᎐CO) and 1056 cmϪ1 (BF4Ϫ); δH 1.01 (3 H,
t, J 7.4 Hz, Fe᎐CCH CH ), 2.18–2.29 (2 H, m, Fe᎐CCH CH ),
᎐
᎐
2
3
2
3
᎐
᎐
2
3
2
3
3.03 (3 H, s, NHMe), 4.82 (5 H, s, C5H5), 7.31–7.36 (6 H, m, Ho
of PPh3), 7.50–7.55 (9 H, m, Hm and Hp of PPh3), 9.84 (1 H, br
3.02–3.07 (1 H, m, Fe᎐CCH CH ), 4.69 (1 H, dd, J 14.7, 4.4,
᎐
2
3
NHCH2Ph), 4.87 (1 H, dd, J 14.7, 6.7, NHCH2Ph), 5.12 (5 H,
d, JPH 1.4, C5H5), 7.07 (2 H, dd, J 7.7, 2.1, Ho of Ph), 7.25 (6 H,
dd, JPH 10.1, JHH 7.7, Ho of PPh3), 7.31–7.36 (3 H, m, Hm and
Hp of Ph), 7.48 (6 H, tq, J 7.5, 2.1, Hm of PPh3), 7.58 (3 H,
tq, J 7.6, 1.9 Hz, Hp of PPh3), 10.11 (1 H, br s, NHCH2Ph);
δC(CD3COCD3) 11.35 (s, Fe᎐CCH CH ), 43.14 (s, Fe᎐
s, NHMe); δ 10.15 (s, Fe᎐CCH CH ), 36.65 (s, NHMe), 41.39
᎐
C
2
3
(s, Fe᎐CCH CH ), 85.68 (s, C H ), 129.19 (d, J 9.5, Cm of
᎐
2
3
5
5
PC
PPh3), 131.12 (s, Cp of PPh3), 132.95 (d, JPC 8.8, Co of PPh3),
133.31 (d, JPC 46.0, Cipso of PPh3), 218.47 (d, JPC 30.2, Fe᎐CO),
268.48 (d, JPC 20.1 Hz, Fe᎐C); δ 66.20; δF Ϫ154.00 and
᎐
P
᎐
᎐
2
3
Ϫ154.05 (1:3); m/z 482 (Mϩ, 100), 454 (M Ϫ CO, 27), 383 (13),
318 (9), 295 (46), 263 (23), 220 (9), 192 (98), 183 (27), 85 (29),
70 (34%). The yield of this reaction could not be improved by
using gaseous methylamine.
CCH2CH3), 53.82 (s, NCH2Ph), 86.42 (s, C5H5), 128.99 (s, Cp of
Ph), 129.25 (s, Cm of Ph), 129.95 (s, Co of Ph), 129.98 (d, JPC 9.2,
Cm of PPh3), 132.00 (s, Cp of PPh3), 133.70 (d, JPC 9.6, Co of
PPh3), 133.91 (d, JPC 43.3, Cipso of PPh3), 136.25 (s, Cipso of Ph),
218.86 (d, JPC 29.1, Fe᎐CO), 273.03 (d, JPC 23.3 Hz, Fe᎐C);
᎐
؊
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Et)(NHEt)}]؉BF
4
(RS)-
δP(CD3COCD3) 67.70 (s, PPh3), Ϫ147.11 (septet, JPF 708.7 Hz,
PF6Ϫ); δF(CD3COCD3) Ϫ69.13 (d, JPF 707.8 Hz, PF6Ϫ); m/z
558 (Mϩ, 87), 530 (M Ϫ CO, 7), 383 (10), 295 (10), 268 (100),
212 (15), 183 (25), 121 (10), 91 (27), 59 (13%).
᎐
5
5
3
19. Reaction of (RS)-17 (1.00 g, 1.80 mmol) with gaseous
ethylamine for 2 h at 0 ЊC afforded (RS)-19 as a yellow foam
(0.73 g, 70%) which could not be crystallised from a number
of solvents. Microanalytical data could not be obtained as
this product contained 5% of [(η5-C5H5)Fe(CO)2(PPh3)]ϩBF4
(RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(CH CH CH CH )-
Ϫ
᎐
5
5
3
2
2
2
3
؊
which could not be separated from the product either by chro-
matography or selective crystallisation; νmax 1954 (Fe᎐CO) and
1057 cmϪ1 (BF4Ϫ); δH 0.85 (3 H, t, J 7.1, NCH2CH3), 1.08 (3 H,
t, J 7.6 Hz, Fe᎐CCH CH ), 2.37–2.56 (2 H, m, Fe᎐CCH CH ),
3.42–3.51 (2 H, m, NCH2CH3), 4.82 (5 H, s, C5H5), 7.15–7.65
(NHMe)}]؉BF4 (RS)-24. Reaction of (RS)-23 (1.18 g, 1.97
mmol) with gaseous methylamine at 0 ЊC for 2 h afforded (RS)-
24 as a yellow foam (0.88 g, 80%). Microanalytical data could
not be obtained for this product which was isolated as a mix-
᎐
᎐
2
3
2
3
ture with [(η5-C5H5)Fe(CO)2(PPh3)]BF4 (10%). This impurity
Ϫ
(15 H, m, PPh3), 9.61 (1 H, br s, NHEt); δC 11.14 (s, Fe᎐
could not be removed by column chromatography or selective
᎐
CCH CH ), 13.95 (s, NCH CH ), 41.31 (s, Fe᎐CCH CH ),
recrystallisation; νmax 1964 (Fe᎐CO) and 1054 cmϪ1 (BF4Ϫ); δH
᎐
2
3
2
3
2
3
44.62 (s, NCH2CH3), 85.34 (s, C5H5), 129.11 (d, JPC 9.6, Cm of
PPh3), 131.10 (s, Cp of PPh3), 132.76 (d, JPC 8.9, Co of PPh3),
0.88 (3 H, t, J 7.1 Hz, Fe᎐CCH CH CH CH ), 1.10–2.50 (6 H,
᎐
2 2 2 3
m, Fe᎐CCH CH CH CH ), 3.00 (3 H, s, NMe), 4.79 (5 H, s,
᎐
2
2
2
3
133.00 (d, JPC 50.5, Cipso of PPh3), 218.12 (d, JPC 28.5, Fe᎐CO),
C5H5), 7.19–7.82 (15 H, m, PPh3), 10.19 (1 H, br s, NHMe);
᎐
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594
1593

View Article Online
δC 13.46 (s, Fe᎐CCH CH CH CH ), 22.66 (s, Fe᎐CCH CH -
vergence R = 0.038, RЈ = 0.031 for 399 parameters. CCDC
᎐
᎐
2
2
2
3
2
2
CH CH ), 27.75 (s, Fe᎐CCH CH CH CH ), 36.12 (s, NMe),
reference number 186/949.
᎐
2
3
2
2
2
3
48.05 (s, Fe᎐CCH CH CH CH ), 85.33 (s, C H ), 129.04 (d, J
᎐
2
2
2
3
5
5
PC
9.8, Cm of PPh3), 131.06 (s, Cp of PPh3), 133.82 (d, JPC 9.8, Co of
PPh3), 133.11 (d, JPC 46.3, Cipso of PPh3), 218.28 (d, JPC 28.5,
Acknowledgements
We thank the EPSRC for a ROPA award.
Fe᎐CO), 267.94 (d, JPC 23.5 Hz, Fe᎐C); δ 66.25; δ Ϫ153.85
᎐
P
F
and Ϫ153.90 (1:3); m/z 510 (Mϩ, 44), 482 (M Ϫ CO, 18),
220 (100), 183 (20), 129 (72), 98 (40%).
References
Deuteriation studies of (RS)-[(ç5-C H )Fe(CO)(PPh ){᎐C(Me)-
1 S. G. Davies, Pure Appl. Chem., 1988, 60, 40.
᎐
5
5
3
(NHCH2Ph)}]؉PF6؊ (RS)-15
2 S. G. Davies, Aldrichimica Acta, 1990, 23, 31.
3 S. G. Davies, I. M. Dordor-Hedgecock, K. H. Sutton and
M. Whittaker, J. Am. Chem. Soc., 1987, 109, 5711.
4 G. J. Baird, S. G. Davies and T. R. Maberly, Organometallics, 1984,
3, 1764.
5 S. G. Davies and T. R. Maberly, J. Organomet. Chem., 1985, 296,
C37.
Method (a). Treatment of a nitrogen degassed solution of 15
(50 mg) in CD3OD with NaOMe (20 mol %) at room temper-
1
ature for 3 d afforded by H NMR analysis (RS)-[(η5-C5H5)-
Ϫ
.
Fe(CO)(PPh ){᎐C(CD )(NDCH Ph)}]ϩPF
᎐
3
3
2
6
6 G. J. Baird, S. G. Davies, R. H. Jones, K. Prout and P. Warner,
J. Chem. Soc., Chem. Commun., 1984, 744.
Method (b). Treatment of a solution of (RS)-15 (100 mg) in
THF (10 mL) with BuLi (1 mol equivalent) at Ϫ78 ЊC for 30
min followed by quenching with CD3OD and concentration in
7 L. S. Hegedus, M. A. Schwindt, S. D. Lombaert and
R. Imwinkelried, J. Am. Chem. Soc., 1990, 112, 2264.
8 A. Davison and D. L. Reger, J. Am. Chem. Soc., 1972, 94, 9237.
9 (a) S. Abbott, S. G. Davies and P. Warner, J. Organomet. Chem.,
1983, 246, C65; (b) B. E. Boland-Lussier and R. P. Hughes,
Organometallics, 1982, 1, 635.
1
vacuo afforded by H NMR analysis (RS)-[(η5-C5H5)Fe(CO)-
(PPh ){᎐C(Me)(NDCH Ph)}]ϩPF Ϫ (RS)-28.
᎐
3
2
6
Method (c). Treatment of a solution of (RS)-15 (100 mg) in
THF (10 mL) with BuLi (3 or more mol equivalents) at Ϫ78 ЊC
for 3 h followed by quenching with either CD3OD or D2O
10 (a) M. L. H. Green, L. C. Mitchard and M. G. Swanick, J. Chem.
Soc. A, 1971, 794; (b) T. Bodnar and A. R. Cutler, J. Organomet.
Chem., 1981, 213, C31; (c) M. Brockhard, J. R. Tucker and
G. R. Husk, J. Am. Chem. Soc., 1983, 105, 258.
11 B. J. Wakefield, Organolithium Methods, Academic Press, London,
1988.
12 S. C. Case-Green, J. F. Costello, S. G. Davies, N. Heaton, C. J. R.
Hedgecock, V. M. Humphreys, M. R. Metzler and J. C. Prime,
J. Chem. Soc., Perkin Trans. 1, 1994, 933.
13 M. Brookhart, Y. Liu, W. Goldman, D. A. Timmers and G. D.
Williams, J. Am. Chem. Soc., 1991, 113, 927.
14 B. K. Blackburn, S. G. Davies and M. Whittaker, Chemical Bonds –
Better Ways to Make Them and Break Them, ed. I. Bernal, Oxford,
1989, vol. 3, pp. 141–223.
15 S. G. Davies, M. R. Metzler, K. Yanada and R. Yanada, J. Chem.
Soc., Chem. Commun., 1993, 658.
16 D. F. Shriver, The Manipulation of Air-Sensitive Compounds,
McGraw-Hill, New York, 1969.
17 J. P. Bibler and A. Wojcicki, Inorg. Chem., 1966, 5, 889.
18 M. Green and D. J. Westlake, J. Chem. Soc. A, 1971, 367.
19 S. Abbott, G. J. Baird, S. G. Davies, I. M. Dordor-Hedgecock,
T. R. Maberly, J. C. Walker and P. Warner, J. Organomet. Chem.,
1985, 289, C13.
and filtration through dry Celite afforded (RS)-[(η5-C5H5)-
Ϫ
Fe(CO)(PPh ){᎐C(CD H)(NDCH Ph)}]ϩPF (RS)-30 which
᎐
3
2
2
6
was recrystallised from CH2Cl2–hexane as yellow microneedles,
m.p. 197–199 ЊC (decomp.) (Found: C, 57.40; H, 4.80; N, 2.03.
C33H28BD3F4FeNOP requires: C, 57.24; H, 4.95; N, 2.02%);
νmax 1958 (Fe᎐CO) and 841 cmϪ1 (PF6Ϫ); δH(CD2Cl2) 2.69 (1
H, br s, Fe᎐CD H), 4.53 (1 H, dd, J 14.6, 4.8, NHCH Ph),
᎐
2
2
4.58 (1 H, dd, J 14.4, 5.9, NHCH2Ph), 4.77 (5 H, s, C5H5), 7.00
(2 H, br d, J 7.3, Ho of Ph), 7.10 (6 H, dd, JPH 10.8, JHH 7.7,
Ho of PPh3), 7.30–7.38 (3 H, m, Hm and Hp of Ph), 7.41 (6 H,
td, J 7.6, 1.9, Hm of PPh3), 7.51 (3 H, tq, J 7.5, 1.7 Hz, Hp
of PPh3); m/z 547 (Mϩ, 68), 519 (M Ϫ CO, 10), 383 (18), 338
(17), 318 (11), 295 (31), 279 (32), 263 (37), 256 (100), 212 (35),
183 (25), 161 (30), 148 (13), 133 (15), 121 (17), 103 (24), 91 (41%).
Crystal structure determination of (R,S)-33
C34H33 BF4FeNOP, M = 589.42, orthorhombic, P22121 (no. 18),
a = 10.603(1), b = 11.894(1), c = 24.779(3) Å (from least squares
fitting of setting angles for 25 reflections 20.1 р θ р 32.9Њ),
U = 3125 Å3, Z = 4, Dx = 1.253 g cmϪ3, Cu-Kα radiation,
orange needles 0.2 × 0.2 × 0.1 mm, µ = 11.99 cmϪ1. 7271 Reflec-
tions measured, 5759 unique (Rmerge = 0.03, Friedel pairs were
not merged) of which 2978 were observed (I у 3σI). At con-
20 S. G. Davies, M. R. Metzler, W. C. Watkins, R. G. Compton,
J. Booth and J. C. Eklund, J. Chem. Soc., Perkin Trans. 2, 1993, 1603.
21 (a) A. C. Cope, C. R. Ganellin, H. W. Johnson, jun., T. V. Van Auken
and H. J. S. Winkler, J. Am. Chem. Soc., 1963, 85, 3276; (b)
D. Parker and R. J. Taylor, Tetrahedron, 1987, 43, 5451.
Received 3rd February 1998; Paper 8/00927I
1594
J. Chem. Soc., Dalton Trans., 1998, Pages 1587–1594