Synthesis and reactivity of achiral and of a novel planar chiral thioferrocenoylsilanes

Article abstract of DOI:10.1016/S0022-328X(01)00944-5

The reactions of thioferrocenoylsilanes with organolithium reagents, dienes and reducing agents which afford α-silyl sulphides, dihydrothiopyranes and α-silyl ferrocenyl thiols, respectively, have been investigated. α-Silyl sulphides were further functionalised through carbodesilylation with aldehydes. We also report the synthesis of a new planar chiral thioferrocenoylsilane that gave good diastereomeric excess in the reaction with t-butyllithium, lithium lutidine and 2,3-dimethylbuta-1,3-diene. The 1,1′-bis-thioferrocenoylsilane, too unstable to be isolated, was trapped in situ with dienes.

Full text of DOI:10.1016/S0022-328X(01)00944-5

Journal of Organometallic Chemistry 637–639 (2001) 407–417
www.elsevier.com/locate/jorganchem
Synthesis and reactivity of achiral and of a novel planar chiral
thioferrocenoylsilanes
Bianca F. Bonini *, Mauro Comes-Franchini, Mariafrancesca Fochi,
Germana Mazzanti, Alfredo Ricci, Massimiliano Tomasulo, Greta Varchi
Dipartimento di Chimica Organica ‘A. Mangini’, Facolta` di Chimica Industriale, Viale Risorgimento 4, 40136 Bologna, Italy
Received 19 January 2001; received in revised form 24 April 2001; accepted 24 April 2001
Abstract
The reactions of thioferrocenoylsilanes with organolithium reagents, dienes and reducing agents which afford a-silyl sulphides,
dihydrothiopyranes and a-silyl ferrocenyl thiols, respectively, have been investigated. a-Silyl sulphides were further functionalised
through carbodesilylation with aldehydes. We also report the synthesis of a new planar chiral thioferrocenoylsilane that gave good
diastereomeric excess in the reaction with t-butyllithium, lithium lutidine and 2,3-dimethylbuta-1,3-diene. The 1,1%-bis-thioferro-
cenoylsilane, too unstable to be isolated, was trapped in situ with dienes. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Ferrocene; Planar chirality; Thioacylsilanes; Thiophilic addition; Diels–Alder reaction; b-Hydroxy sulphides; b-Amino sulphides
1. Introduction
application as ligands in asymmetric synthesis. In con-
nection with our ongoing interest in the chemistry of
thioacylsilanes [13], a class of versatile compounds
characterised by a remarkably high reactivity of the
carbon–sulphur double bond, we developed the synthe-
sis of new thioferrocenoylsilanes 1a–1c [14] (Scheme 1)
starting from the corresponding acylsilanes through an
easy thionation with Lawesson’s reagent (LR) in THF
at room temperature. Compounds 1a–1c, as other
thioacylsilanes [13], showed a remarkable high reactiv-
ity in Diels–Alder and 1,3-dipolar cycloaddition reac-
tions which allowed the synthesis of compounds
containing the ferrocenyl substituted carbon–sulphur–
silicon moiety [14].
In this paper we describe further studies on the
reactivity of compounds 1a–1c as well as the synthesis
and the reactivity of 1,1%-disubstituted bis-thioferro-
cenoylsilane and of a planar chiral thioferrocenoylsilane
with high potential as starting materials for the synthe-
sis of ligands containing sulphur and the ferrocene
moiety.
Since the discovery of ferrocene in 1951 [1], its chem-
istry has been investigated intensively [2]. In particular
the use of ferrocenyl ligands in organic catalysis still
continues to grow. Among these ligands the 1,1%-bis-
derivatives [2] such as 1,1%-bis(diphenylphosphino)-
ferrocene (dppf) and a large variety of enantiopure
1,2-disubstituted ferrocenes with planar chirality have
received considerable attention [3]. Several efficient syn-
theses of 1,2-disubstituted ferrocenes with planar chiral-
ity are based on the diastereoselective ortho-lithiation
of ferrocenyl derivatives containing a chiral ortho-di-
recting group such as a tertiary amine [4], an acetal [5],
a sulphoxide [6] or an oxazoline [7,3c]. More recently
enantioselective ortho-lithiation of monosubstituted fer-
rocenes in the presence of a tertiary chiral amine has
been reported for the synthesis of enantiomerically
enriched 1,2-disubstituted ferrocenes [8]. Sulphur-con-
taining compounds such as hydroxy and amino sul-
phides [9], pyridine thiols [10a,b] and thioethers [10c],
amino thiols [11] and imine sulphides [12] have found
* Corresponding author. Tel.: +39-51-6443626; fax: +39-51-
2093654.
E-mail address: bonini@ms.fci.unibo.it (B.F. Bonini).
Scheme 1.
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00944-5

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B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
Table 1
Products 2a–2g exhibit a moderate stability on silica
and were purified by chromatography on deactivated
neutral alumina. The b-amino sulphide 2d was obtained
by reaction of 1a with the monolithium derivative of
2,6-lutidine. It is worth to note that the same lithium
derivative gave only products deriving from the car-
bophilic addition to other non-enethiolisable thioke-
tones like thioadamantanone [10a] and thiofenchone
[10b], the final products of these reactions being pyri-
dine thiols.
Reaction of thioferrocenoylsilanes 1a and 1b with organolithium
reagents
Compound 2c was subjected to further synthetic
transformations by performing a fluorodesilylation re-
action with anhydrous cesium fluoride in the presence
of a carbon electrophile such as p-tolualdehyde. The
reaction led to a diastereomeric mixture of b-hydroxy
sulphides 3 in an overall yield of 52% beside a 30%
yield of tert-butyl ferrocenylmethyl sulphide 4 (Scheme
2) arising from a competitive protiodesilylation of 2c.
A very low d.e. value (10%) was determined by
1
integration of the signals in the H-NMR spectrum of
the CHꢀOH of the major (at l=5.01) and of the minor
isomer (at l=5.18). An higher d.e. value (42%) was
obtained, though with a lower yield of the diastereoiso-
mers 3 (30%) with a shorter reaction time (see Section
4). The relative stereochemistry of the two chiral cen-
tres has not been assigned.
Scheme 2.
2.2. Reduction of thioferrocenoylsilanes
Thiols have been applied largely as nucleophiles in
the conjugated addition [17] as well as in the asymmet-
ric version of this reaction [18]. Furthermore the ring
opening reaction of aziridines and epoxides [9] by thiols
has also found application in recent years. The reduc-
tion of thioketones to thiols is a procedure known since
many years [19], however, only recently asymmetric
versions of this reaction have been reported [20]. The
reduction of 1a and 1b (Scheme 3) was performed with
a 1 M solution of LiAlH4 in THF at −30 °C. After
the usual work up, the thiols 5a and 5b were obtained
in 75 and 96% yields, respectively, and were character-
ised fully. An asymmetric version of this reaction was
attempted both with baker’s yeast (BY) and with the
CBS method [21]. The reaction with BY was performed
on the thione 1a in water at 30 °C. Due to the long
reaction time (3 days) necessary for the disappearance
of the blue colour of the thione, an extensive decompo-
sition occurred and the thiol 5b was isolated after
chromatography in 25% yield. Following the CBS pro-
cedure at 0 °C the reactions of thiones 1a and 1b were
completed in 40 min and the thiols 5a and 5b were
obtained in 47 and 39% yield, respectively, after chro-
matography on deactivated neutral alumina. Any at-
tempt to measure the optical rotation of both the thiols
5a and 5b failed, because of the very intense yellow
colour of the solution. Furthermore the evaluation of
Scheme 3.
2. Results and discussion
2.1. Reaction of thioferrocenoylsilanes with
organolithium reagents
It is well known that thiocarbonyl compounds can
undergo addition with organometallic reagents
(organolithium and Grignard reagents) in high regiose-
lective either thiophilic [15] or carbophilic [16] manner
under appropriate experimental conditions. Thioacylsi-
lanes react with organolithium reagents only at the
sulphur probably because of the stabilising effect of the
silyl group on the intermediate a-silyl carbanion [13]. In
agreement with this behaviour thioferrocenoylsilanes 1a
and 1b react with organolithium reagents affording
a-silyl sulphides 2a–2g in moderate to very good yields
(Table 1).

B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
409
Scheme 4.
Scheme 6.
2.4. Synthesis and reacti6ity of a planar chiral
thioferrocenoylsilane
1
the enantiomeric excess performing the H-NMR spec-
trum in the presence of Pirkle’s alcohol (S(+)-
1(antryl)-2,2,2-trifluoroethanol) was unsuccessful, since,
we did not observe any splitting of signals on the
racemic derivatives.
For the synthesis of a suitable precursor for the
preparation of the first planar chiral thioferrocenoylsi-
lane we adopted the strategy reported by Kagan based
on the diastereoselective ortho-lithiation of (S)-ferro-
cenyl p-tolylsulphoxide (10) ([h]D=310° (c=0.57,
CHCl3), lit: [h]D=314° (c=0.5)) with LDA at
−78 °C [6,23]. By electrophilic quenching with CO2,
the carboxylic acid 11 was isolated as a single enan-
tiomer in good yield (75%) and excellent diastereoselec-
With the aim of determining the enantiomeric excess
obtained during the reduction of thioacylsilanes 1a and
1b, we tried different derivatisations of 5a and 5b. Any
attempt of trapping 5 with MeI and any ring opening
reactions with epoxides or aziridines failed and the
starting thiols were recovered, whereas the reaction
with chloroacetone in dry ether in the presence of one
equivalent of DPEA (diisopropylethylamine) gave the
adducts 6a and 6b in 73 and 75% yield, respectively
(Scheme 4). These products resulted rather unstable
and partially decomposed during the acquisition time
for the 13C-NMR spectrum.
1
tivity (d.e.\98%), calculated by H-NMR (Scheme 6).
The enantiomerical purity has been established by com-
parison of the 1H-NMR spectrum of the optically
active and of the racemic acid 11 (obtained with the
same procedure starting from the racemic sulphoxide
10) in the presence of Pirkle’s alcohol (see Section 4).
The relative stereochemistry has been assigned (SFc
and SS) according to Kagan’s results [23] obtained by
quenching the lithiated sulphoxide 10 with a wide range
of electrophilic reagents.
2.3. 1,1%-Bisferrocenylthioacylsilane
The 1,1%-bisferrocenylthioacylsilane (7) was prepared
by thionation with LR at room temperature of the
corresponding acylsilane 8 [22], which in turn was
obtained by nucleophilic silylation with bis(di-
methylphenylsilyl)lithium cyanocuprate of the corre-
sponding ferrocenoyldichloride [22]. All the attempts to
isolate the blue bis-thione 7 by chromatography failed.
The blue colour of the reaction mixture disappeared on
standing and a new compound was found, among other
unidentified products, probably arising from an in-
tramolecular reaction between the two thiocarbonylic
functions. In fact, a peak at m/z=544 corresponding to
the molecular ion of the thione plus two hydrogens was
detected in the mass spectrum. For this reason 7 was
trapped in situ with 2,3-dimethylbuta-1,3-diene. The
bis-adduct 9 was isolated in 60% yield and was charac-
terised fully (Scheme 5).
Since the conversion of product 11 into the corre-
sponding chloride failed, 11 was deoxygenated to the
sulphide 12 by reaction with Lawesson’s reagent at
room temperature in 50% yield (Scheme 7). This
method [24] was found to be the best one among the
others we tested for the reduction of 11: SmI2 [25] gave
complete decomposition; triethylphosphite/iodine/NaI
[26] gave a lower yield of 12 (12%) and the reduction
with a HCl (g) saturated solution of acetonitrile [27],
left 11 unreacted.
The sulphide 12 ([h]D= −31.4° (c=0.49, CHCl3))
was found to be enantiomerically pure (e.e. \98%
within the experimental error) by comparison of its
1H-NMR spectrum, in the presence of Pirkle’s alcohol,
with the spectrum of the same sulphide obtained start-
ing from the sulphoxide 10 having an enantiomeric
excess of only 88% ([h]D=280° (c=0.5, CHCl3) (see
Scheme 5.

410
B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
1
1
Section 4). The H-NMR spectrum of this sulphide, in
the H-NMR of the crude reaction mixture. The major
diastereoisomer of 16 could be separated by chro-
matography on preparative TLC and characterised
fully. The reaction with the monolithium derivative of
2,6-lutidine yielded the b-ammino sulphides 17 in 53%
yield with a d.e. equal to 50% (Scheme 8). The reaction
of 15 with 2,3-dimethyl-buta-1,3-diene at room temper-
ature took place in a very short reaction time and
afforded two diastereomeric cycloadducts 18 in a 3.5:1
ratio (d.e.=56%) and in 78% yield. The two
diastereoisomers could be separated by chromatogra-
phy and were characterised fully. The same reaction
was repeated at −20 °C giving the two isomers in a
4.9:1 ratio (d.e.=76%).
the presence of Pirkle’s alcohol, showed two peaks in a
7:93 ratio at 4.34 and 4.31 ppm, respectively, the H-
1
NMR spectrum of the enantiomerically pure 12 showed
only the signal at 4.31 ppm. Moreover the racemic
sulphide 12, obtained starting from the racemic
sulphoxide 10, gave, in the presence of Pirkle’s alcohol,
the two peaks in a 1:1 ratio.
Sulphide 12 was converted into the corresponding
chloride 13 in quantitative yield by reaction with oxa-
lylchloride and then into the acylsilane 14 ([h]D=
−683° (c=0.2, CHCl3) in 58% yield and e.e.\98% by
nucleophilic silylation at −78 °C with dimethyl-
phenylsilyl lithiumcyanocuprate. Reaction of 14 with
LR in THF at room temperature gave the thione 15
(Scheme 7) in 94% yield after purification by chro-
matography on fluorisil. The thioacylsilane 15 was
characterised fully and was found to be enantiomeri-
cally pure (e.e.\98%) but it was not possible to mea-
sure its optical rotation because of the very intense blue
colour of the solution. The enantiomerical purity of
compounds 14 and 15 was determined by comparison
3. Conclusions
A new planar enantiomerically pure chiral thioferro-
cenoylsilane has been synthesised in good yield and its
reactivity investigated. Dihydrothiopyrans and a-silyl
sulphides were obtained in the reaction with dienes and
organolithium derivatives in good yields and high
diastereoselectivity. A similar chemical behaviour was
observed with the achiral derivatives. Further studies
are in progress for obtaining from thioferrocenoylsi-
lanes suitable compounds to be used as ligands in
asymmetric synthesis.
1
of their H-NMR spectra with those of the correspond-
ing compounds obtained starting from the sulphoxide
10 with e.e.=88% in the presence of Pirkle’s alcohol.
The thione 15 reacted with t-BuLi at −78 °C in few
minutes and afforded the a-silyl sulphides 16 (Scheme
8) in 68% yield with a d.e. equal to 77% calculated from
Scheme 7.
Scheme 8.

B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
411
4. Experimental
4.2.1. Methyl[( ferrocenyl)(trimethylsilyl)methyl]sulphide
(2a)
Following the above general procedure starting from
1a and MeLi (1.6 M in Et2O), 2a was obtained in 41%
yield as a solid. M.p.=47 °C. 1H-NMR (300 MHz,
CDCl3): l −0.02 (s, 9H, SiMe3), 2.30 (s, 3H, SMe),
2.56 (s, 1H, CH), 3.95–4.10 (4m, 4H, FcH), 4.16 (s, 5H,
FcH). EIMS; m/z: 318 [M+], 186 [Fc], 73 [SiMe3].
HRMS Found: 318.0513. Calc for C15H22FeSSi:
318.0561.
4.1. General procedures
Melting points (uncorrected) were determined with a
Bu¨chi melting point apparatus. 1H- and 13C-NMR
spectra were recorded using CDCl3 solutions at 300 and
75.46 MHz, respectively, with a Varian Gemini 300.
Chemical shifts (l) are reported in ppm relative to
1
CHCl3 (l=7.26 for H and l=77.0 for 13C). J values
are given in Hz. 13C-NMR spectral assignments were
made by DEPT experiments. IR spectra were recorded
on a Perkin–Elmer model 257 grating spectrometer.
Mass spectra were obtained using a VG 7070-E spec-
trometer at an ionising voltage of 70 eV. [h]2D0 values
were determined with Perkin–Elmer Polarimeter 341.
In the characterisation of the new compounds, oily
products, because of the small scale used for the prepa-
ration, have been characterised by accurate mass mea-
surements. Reactions were conducted in oven-dried
(120 °C) glassware under a positive Ar atmosphere.
Transfer of anhydrous solvents or mixtures was accom-
plished with oven-dried syringes/septum techniques. Te-
trahydrofuran was distilled from sodium–benzo-
phenone just prior to use and stored under Ar. Di-
ethylether was distilled from P2O5. Dichloromethane
was passed through basic alumina and distilled from
CaH2 prior to use. Other solvents were purified by
standard procedures. Light petroleum ether refers to
the fraction with boiling point (b.p.) 40–60 °C. The
reactions were monitored by TLC performed on silica
gel plates (Baker-flex IB2-F). Column chromatography
was performed with Merck silica gel 60 (70–230 mesh).
Preparative thick layer chromatography was carried out
on glass plates using a 1 mm layer of Merck silica gel
60 Pf254. All chemicals were used as obtained or purified
by distillation as needed. S(+)-(9-anthryl)-2,2,2-tri-
fluoroethanol was purchased by Fluka, (S)-2-methyl-
CBS-oxazaborolidine (1 M solution in toluene) was
purchased by Aldrich. Thioacylsilanes 1a and 1b were
prepared as previously reported by us [14] and (S)-fer-
rocenyl p-tolyl sulphoxide 10 was prepared following
the literature procedure [23].
4.2.2. n-Butyl[( ferrocenyl)(trimethylsilyl)methyl]sulphide
(2b)
Following the above general procedure starting from
1a and n-BuLi (1.6 M in hexane), 2b was obtained in
80% yield as a pale yellow oil.1H-NMR (300 MHz,
CDCl3): l −0.04 (s, 9H, SiMe3), 0.93 (t, J=6.0 Hz,
3H, CH3), 1.35–1.70 (m, 4H, 2CH2), 2.61 (s, 1H, CH),
2.73 (t, J=7.0 Hz, 2H, SCH2), 3.90–4.10 (4m, 4H,
FcH), 4.14 (s, 5H, FcH). 13C-NMR (75.46 MHz,
CDCl3): l −2.00 (SiMe3), 13.81 (CH3), 22.16 (CH2),
31.87 (CH2), 32.67 (CH), 34.30 (CH2), 67.51, 67.80,
68.66, 69.46, 70.27 (FcCH), 91.78 (FcC). EIMS: m/z;
360 [M+], 303 [M+−C4H9], 186 [Fc], 73 [SiMe3].
HRMS Found: 360.1089. Calc. for C18H28FeSSi:
360.1030.
4.2.3. t-Butyl[( ferrocenyl)(trimethylsilyl)methyl]sulphide
(2c)
Following the above general procedure starting from
1a and t-BuLi (1.5 M in pentane), 2c was obtained in
1
43% yield. H-NMR (300 MHz, CDCl3): l 0.09 (s, 9H,
SiMe3), 1.37 (s, 9H,), 2.68 (s, 1H, CH), 4.04–4.12 (4m,
4H, FcH), 4.17 (s, 5H, FcH). 13C-NMR (75.46 MHz,
CDCl3): l −0.96 (SiMe3), 27.49 (CH), 31.79 (CH3),
43.62 (C), 66.54, 67.34, 68.55, 68.85, 69.42 (FcH), 95.19
(FcC). EIMS; m/z: 360 [M+], 303 [M+−C4H9], 186
[Fc], 73 [SiMe3]. HRMS Found: 360.1101. Calc. for
C18H28FeSSi: 360.1030.
4.2.4. (6-Methyl-2-pyridinyl)methyl
ferrocenyl(trimethylsilyl)methyl sulphide (2d)
4.2. Reaction of 1a and 1b with organolithium
reagents. General procedure
Following the above general procedure starting from
1a and lithium lutidine, prepared from freshly distilled
lutidine (1.2 ml) in 12.5 ml of dry THF at −60 °C and
n-BuLi (11 mmol), 2d was obtained in 81% yield as a
yellow solid. M.p.=54 °C. 1H-NMR (300 MHz,
CDCl3): l −0.10 (s, 9H, SiMe3), 2.54 (s, 3H, CH3),
2.82 (s, 1H, CH), 3.90–4.80 (11H, FcH, CH2), 7.01 (d,
J=7.5 Hz, 1H, ArH), 7.19 (d, J=7.5 Hz, 1H, ArH),
7.53 (t, J=9 Hz, 1H, ArH). EIMS; m/z: 409 [M+], 303
[M+−C7H8N], 186 [Fc], 107 [C7H9N]. HRMS Found:
409.0914. Calc. for C21H27FeNSSi: 409.0983.
To a stirred solution of thioacylsilane 1 (0.13 mmol)
in dry THF (5 ml) under Ar at −78 °C, alkyl lithium
reagent (0.15 mmol) was added dropwise. The colour of
the solution rapidly changed from blue to red–yellow.
The mixture was concentrated under reduced pressure
and then chromatographed on deactivated neutral alu-
mina (light petroleum–diethyl ether, 8:1) affording the
a-silyl sulphide as a yellow–orange product.

412
B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
4.2.5. Methyl {( ferrocenyl)[dimethyl(phenyl)silyl]}-
methyl sulphide (2e)
ture (r.t.) for 40 h, the reaction mixture was quenched
with NH4Cl and extracted with Et2O. The organic
phase was dried and concentrated. A H-NMR spec-
1
Compound 2e was obtained in 62% yield starting
from 1b and MeLi (1.6 M in Et2O). 1H-NMR (300
MHz, CDCl3): l 0.22 (s, 3H, SiMe), 0.31 (s, 3H, SiMe),
2.13 (s, 3H, SCH3), 2.72 (s, 1H, CH), 3.77 (m, 1H,
FcH), 3.98–4.20 (3m, 3H, FcH) 4.11 (s, 5H, FcH), 7.30
(bd, J=8.3 Hz, 3H, ArH), 7.42 (bd, J=8.3 Hz, 2H,
ArH). 13C-NMR (75.46 MHz, CDCl3): l −4.2, −4.0
(SiMe), 18.4 (SCH3), 34.8 (CH), 66.4, 66.8, 67.1, 68.0,
68.6 (FcH), 91.2 (ArC), 127.2, 128.9, 134.2 (ArCH).
EIMS; m/z: 380 [M+], 365 [M+−Me], 333 [M+−
SMe], 245 [M+−SiMe2Ph], 135 [SiMe2Ph]. HRMS
Found: 380.0791. Calc. for C20H24FeSSi: 380.0717. IR
(CCl4, cm−1): 1105 (SiPh), 1241 (SiMe), 1425 (SiPh).
trum of the reaction mixture showed a d.e. value of
41% calculated by integration of signals of the CHꢀOH
of the major (at l=5.01) and of the minor
diastereoisomer (at l=5.18). The crude was then
purified by preparative TLC (light petroleum–diethyl
ether, 10:1) to yield, as the higher Rf product, tert-butyl
ferrocenyl methyl sulphide (4) in 33% yield, as the
second Rf product the major diastereoisomer of 3 in
19% yield, and as the lower Rf product the minor
diastereoisomer of 3 in 8% yield. The same reaction
repeated using a longer reaction time (60 h) afforded
the two diastereoisomers of 3 in 52% yield and with a
d.e. equal to 10% beside 31% yield of 4.
4.2.6. n-Butyl {( ferrocenyl)[dimethyl(phenyl)silyl]}-
methyl sulphide (2f)
4.3.1. 2-(t-Butylsulphanyl)-2-ferrocenyl-1-(4-
methylphenyl)-1-ethanol (major isomer)
Yellow oil. H-NMR (300 MHz, CDCl3): l 1.42 (s,
Compound 2f was obtained in 66% yield starting
1
from 1b and n-BuLi (1.6 M in hexane). H-NMR (300
1
MHz, CDCl3): l 0.21 (s, 3H, SiMe), 0.30 (s, 3H, SiMe),
0.88 (t, J=6.8 Hz, 3H, CH3), 1.35 (m, 2H, CH2), 1.50
(m, 2H, CH2), 2.54 (m, 2H, SCH2), 2.78 (s, 1H, CH),
3.75–4.05 (m, 4H, FcꢀH), 4.11 (s, 5H, FcH), 7.20 (m,
3H, ArH), 7.35 (bd, 2H, ArH). 13C-NMR (75.46 MHz,
CDCl3): l −4.0, −4.4 (SiMe), 13.7 (CH3), 22.1, 31.7
(CH2), 32.6 (CH), 34.43 (CH2) 66.2, 67.0, 67.4, 68.0,
68.6 (FcCH), 91.7 (FcC), 127.2, 127.4, 129.1, 134.1
(ArCH), 137.3 (ArC). EIMS; m/z: 422 [M+], 365 [M+
−C4H9], 286 [M+−HSiMe2Ph], 135 [SiMe2Ph].
HRMS Found: 422.1143. Calc. for C23H30FeSSi:
422.1187. IR (CCl4, cm−1): 1104 (SiPh), 1237 (SiMe),
1424 (SiPh).
9H, t-Bu), 2.32 (s, 3H, CH3), 3.41 (d, 1H, J=3.6 Hz,
SCH), 3.55 (m, 1H, FcH), 3.94 (m, 2H, FcH), 4.12, (m,
2H, FcH), 4.15 (s, 5H, FcH), 5.01 (dd, 1H, J1=J2=3.7
Hz, CHOH), 7.06 (bs, 4H, ArH). 13C-NMR (75.46
MHz, CDCl3): l 21.15, 31.89 (CH3), 44.15 (C), 50.77
(CH), 66.54, 67.83, 68.34, 69.01, 69.13 (FcCH), 75.84
(CH), 86.49, (FcC), 126.64, 128.35 (ArCH), 136.75,
138.37 (ArC). EIMS; m/z: 408 [M+], 287 [M+−p-Tol-
CHOH], 91 [C7H7], 57 [C4H9]. HRMS Found:
408.1261. Calc. for C23H28FeOS: 408.1210. IR (CCl4,
cm−1): 3450 (OH).
4.3.2. 2-(t-Butylsulphanyl)-2-ferrocenyl-1-(4-
methylphenyl)-1-ethanol (minor isomer)
Yellow oil. H-NMR (300 MHz, CDCl3): l 1.17 (s,
4.2.7. t-Butyl {( ferrocenyl)[dimethyl(phenyl)silyl]}-
methyl sulphide (2g)
1
Compound 2g was obtained in 78% yield starting
9H, t-Bu), 2.35 (s, 3H, CH3), 3.40 (d, 1H, J=5.3 Hz,
SCH), 3.80 (d, 1H, J=4.7 Hz, OH), 4.01 (m, 1H,
FcH), 4.10 (m, 1H, FcH), 4.15 (m, 1H, FcH), 4.20 (s,
5H, FcH), 4.37 (m, 1H, FcH), 5.18 (dd, 1H, J1=J2=
4.8 Hz, CHOH), 7.16 (d, 2H, J=8.0 Hz ArH), 7.30 (d,
2H, J=8.0 Hz, ArH). 13C-NMR (75.46 MHz, CDCl3):
l 21.10, 31.61 (CH3), 44.08 (C), 51.28 (CH), 68.00,
69.09 (FcH), 75.63 (CH), 91.94 (FcC), 126.82, 128.78
(ArCH), 137.09, 139.73 (ArC). MS; m/z: 408 [M+], 287
[M+−p-TolCHOH], 91 [C7H7], 57 [C4H9]. HRMS
Found: 408.1278. Calc. for C23H28FeOS: 408.1210. IR
(CCl4, cm−1): 3450 (OH).
1
from 1b and t-BuLi (1.5 M in pentane). H-NMR (300
MHz, CDCl3): l 0.32 (s, 3H, SiMe), 0.38 (s, 3H, SiMe),
1.26 (s, 9H, t-Bu), 2.91 (s, 1H, CH), 3.89 (m, 2H, FcH),
3.97 (m, 2H, FcH), 4.05 (s, 5H, FcH), 7.36 (m, 3H,
ArH), 7.53 (m, 2H, ArH). 13C-NMR (75.46 MHz,
CDCl3): l −2.3 (SiMe), −3.3 (SiMe), 27.4 (CH), 31.6
(CH3), 43.8 (C), 66.2, 66.8, 68.6, 68.9, 68.7 (FcCH),
93.1 (FcC), 127.5, 129.0, 134.5 (ArCH), 138.6 (ArC).
EIMS; m/z: 422 [M+], 365 [M+−C4H9], 186 [Fc], 135
[SiMe2Ph]. HRMS Found: 422.1201. Calc. for
C23H30FeSSi: 422.1187.
4.3. Carbodesilylation of 2c
4.3.3. t-Butyl ferrocenyl methyl sulphide (4)
To 0.1 g (0.66 mmol) of flame dried under high
vacuum (0.1 mm Hg) cesium fluoride a solution of 2c
(79 mg, 0.22 mmol) in anhydrous CH3CN (3 ml) and
freshly distilled p-tolualdehyde (0.15 ml, 1.3 mmol)
were added under Ar. After stirring at room tempera-
1H-NMR (300 MHz, CDCl3): l 1.31 (s, 9H, t-Bu),
3.55 (s, 2H, CH2), 4.06 (m, 2H, FcH), 4.13 (s, 5H,
FcH), 4.16 (m, 2H, FcH). 13C-NMR (75.46 MHz,
CDCl3): l 28.35 (CH2), 30.93 (t-Bu), 42.49 (C), 67.73,
68.62, 68.71 (FcCH), 85.32 (FcC).

B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
413
4.4. Reduction of 1a and 1b with LiAlH4
4.6. Reduction of 1a with baker’s yeast
To a solution of 1a or 1b (0.5 mmol) in 5 ml of dry
THF, under Ar atmosphere cooled to −30 °C, a
1 M solution of LiAlH4 in THF was added dropwise
(0.52 mmol). The colour of the solution changed
immediately from blue to yellow and the reaction
mixture was treated with 2 ml of EtOAc then with
2 ml of HCl (2%) and 3 ml of saturated solution of
NH4Cl. The organic layer was extracted with Et2O,
dried and concentrated under reduced pressure. Chro-
matography on deactivated neutral alumina gave the
thiols 5a or 5b in yield 75 and 96%, respectively, as
yellow oils.
To a stirred suspension of 3 g of baker’s yeast in 50
ml of tap water at r.t., 130 mg (0.43 mmol) of 1a
dissolved in 3 ml of n-hexane and 5 g of sugar were
added. Stirring was continued for 3 days with further
addition of 5 g of sugar dissolved in 50 ml of water.
The aqueous suspension was extracted with n-hexane
and the organic phase was dried and concentrated
under reduced pressure. Chromatography (light
petroleum–Et2O, 10:1) on deactivated neutral alumina
gave the thiols 5a in 25% yield.
4.6.1. 1-{[Ferrocenyl(trimethylsilyl)methyl]sulphanyl}-
acetone (6a) or 1-{[ ferrocenyl[dimethyl(phenyl)
silyl]methyl]sulphanyl}acetone (6b)
4.4.1. Compound 5a
To a solution of 5a or 5b (0.25 mmol) in 10 ml of dry
Et2O under Ar, chloroacetone (2.5 mmol) and diiso-
propylethylamine (0.28 mmol) were added dropwise.
After 3 h the starting thiol disappeared (TLC light
petroleum–Et2O, 10:1) and the mixture was concen-
trated in vacuo. Chromatography on deactivated neu-
tral alumina gave the sulphide 6a or 6b as yellow oils in
73 and 75% yield, respectively.
1H-NMR (300 MHz, CDCl3): l −0.02 (s, 9H,
SiMe3). 1.83 (d, 1H, J=5.0 Hz, SH), 3.08 (d, 1H,
J=5.0 Hz, CH), 4.03 (m, 1H, FcH), 4.06 (m, 2H,
FcH), 4.09 (m, 1H, FcH), 4.21 (s, 5H, FcH). 13C-NMR
(75.46 MHz, CDCl3): l −3.08 (SiMe3), 26.72 (CH),
65.96, 66.54, 67.02, 68.11, 68.52 (FcCH), 76.10 (FcC).
EIMS; m/z: 304 [M+], 271 [M+−SH], 230 [M+
−HSiMe3], 186 [Fc], 73 [SiMe3]. HRMS Found:
304.0435. Calc. for C14H20FeSSi: 304.0404.
4.6.2. Compound 6a
1H-NMR (300 MHz, CDCl3): 0.22 (s, 9H, SiMe3),
2.34 (s, 3H, CH3), 2.75 (s, 1H, CH), 3.31 (d, 1H, J=9.5
Hz, CH2), 3.51 (d, 1H, J=9.5 Hz, CH2), 3.95–4.00 (m,
4H, FcH), 4.22 (s, 5H, FcH). EIMS; m/z: 360 [M+],
303 [M+−CH2COCH3], 186 [Fc], 56 [Fe].
4.4.2. Compound 5b
1H-NMR (300 MHz, CDCl3): l 0.25 (s, 3H, SiMe),
0.30 (s, 3H, SiMe),). 1.77 (bs, 1H, SH), 3.26 (bs, 1H,
CH), 3.89 (bs, 1H, FcH), 4.03 (bs, 1H, FcH), 4.09 (bs,
1H, FcH), 4.14 (bs, 1H, FcH), 4.19 (s, 5H, FcH), 7.37
(m, 5H, ArH). 13C-NMR (75.46 MHz, CDCl3): l
−5.15, −4.54 (SiMe), 26.21 (CH), 66.21, 66.56, 67.00,
68.52 (FcCH), 127.61, 132.95, 134.24 (ArCH), 129.21
(ArC). EIMS; m/z: 366 [M+], 334 [M+−S], 230 [M+
−HSiMe2Ph], 135 [SiMe2Ph]. HRMS Found:
366.0515. Calc. for C19H22FeSSi: 366.0561.
4.6.3. Compound 6b
1H-NMR (300 MHz, CDCl3): l 0.20 (s, 3H, SiMe),
0.24 (s, 3H, SiMe), 2.02 (s, 3H, CH3), 2.88 (s, 1H, CH),
3.04 (d, 1H, J=12.5 Hz, CH2), 3.29 (d, 1H, J=12.5
Hz, CH2), 3.70–4.05 (m, 4H, FcH), 4.07 (s, 5H, FcH),
7.20–7.50 (m, 5H, ArH). EIMS; m/z: 422 [M+], 365
[M+−CH2COCH3], 333 [M+−SCH2COCH3], 230
[M+−CH2COCH3ꢀSiMe2Ph],186 [Fc], 135 [SiMe2Ph].
4.5. Reduction of 1a and 1b with CBS methodology
[21]
4.7. Thionation of 8
A solution of 0.15 ml of BH3·DMS (2 M in THF,
0.294 mmol) in 6 ml of THF was slowly added at 0 °C
to a solution of 0.088 ml (0.088 mmol, 1 M in toluene)
of (S)-2-methyl-CBS-oxazaborolidine (MeꢀCBS) in 4
ml of THF. After few minutes a solution of 88.9 mg
(0.294 mmol) of 1a in 5 ml of THF was added. After
1 h the reaction was quenched with 1 ml of MeOH
and 2 ml of saturated aqueous solution of NH4Cl
and extracted with Et2O. Chromatography (light
petroleum–Et2O, 10:1) on deactivated neutral alumina
gave the thiol 5a in 47% yield. Through the
same reaction starting from 1b, 5b was obtained in 39%
yield.
To stirred solution of acylsilane 8 [22] (48 mg, 0.094
mmol) in 3 ml of dry THF at r.t., 76 mg (0.188 mmol)
of Lawesson’s reagent was added. The red colour of the
solution rapidly changed to deep blue. After 15 min, a
TLC (light petroleum–Et2O, 10:1) showed the disap-
pearance of the starting acylsilane and dimethylbuta-
1,3-diene (0.4 ml) was added. The mixture was reacted
for 12 h. The solution was concentrated in vacuo and
the residue was chromatographed on fluorisil affording
1
9 (42 mg) in 63% yield as a yellow oil. H-NMR (300
MHz, CDCl3): l 0.55 (2s, 12H, SiMe2), 1.45 (s, 12H,
4CH3), 3.15 (bs, 4H, 2CH2), 3.50 (bs, 4H, 2CH2), 4.45
(bs, 4H, FcH), 4.80 (bs, 4H, FcH), 7.10–7.65 (m, 10H,

414
B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
ArH). EIMS; m/z: 706 [M+], 135 [SiMe2Ph]. HRMS
Found: 706.2268. Calc. for C40H50FeS2Si2: 706.2242.
acid 11 showed the presence of only one enantiomer
(e.e.\98%).
4.7.3. (SFc)-2-(p-Tolylsulphanyl)-ferrocenecarboxylic
acid (12)
4.7.1. Ferrocenyl p-tolyl sulfoxide (10)
A solution of m-chloroperbenzoic acid (2.0 mmol) in
CH2Cl2 was added dropwise to a solution of p-tolyl
ferrocenyl sulphide [28] (0.6 g, 2.0 mmol) in CH2Cl2 at
0 °C. After disappearance of the starting sulphide
(TLC light petroleum–EtOAc, 5:1) the organic layer
was washed six times with a saturated solution of
NaHCO3 then dried and concentrated in vacuo. Chro-
matography with light petroleum–EtOAc (5:1) af-
forded as the first Rf fraction p-tolyl ferrocenyl
sulphone (4% yield) and as the second Rf fraction the
racemic sulphoxide 10 (74% yield).
To a stirred solution of (SFcSS)-11 (0.368g, 1.0 mmol)
in 20 ml of dry THF at r.t., 0.44 g (1.1 mmol) of
Lawesson’s reagent was added. After 1 h the solution
was concentrated in vacuo and the residue was chro-
matographed on preparative TLC affording (SFc)-12 in
50% yield (0.18 g, 0.51 mmol). Red solid. M.p.=135–
137 °C (Et2O–n-hexane). [h]D= −31.4° (c=0.49,
1
CHCl3). H-NMR (300 MHz, CDCl3): l 2.30 (s, 3H,
CH3), 4.35 (s, 5H, FcH), 4.58 (t, 1H, J=2.7 Hz, FcH),
4.62 (dd, 1H, J1=2.7, J2=1.6 Hz, FcH), 5.11 (dd, 1H,
J1=2.7, J2=1.6 Hz, FcH), 7.09 (m, 4H, ArH). 13C-
NMR (75.46 MHz, CDCl3): l 20.99 (CH3), 71.82,
71.92, 73.02, 78.04 (FcCH), 81.49 (FcC), 128.91, 129.82
(ArCH) 133.22, 136.87 (ArC), 173.94 (CO). EIMS; m/z:
352 [M+], 214 (FcCOH). Anal. Found: C, 61.22; H,
4.66. Calc. for C18H16FeO2S: C, 61.36; H, 4.58%. IR
(CCl4, cm−1): 1677 (COOH).
4.7.2. (SFcSS)-2-(p-Tolylsulphinyl)-ferrocenecarboxylic
acid (11)
To a stirred suspension of (S)-ferrocenyl p-tolyl
sulphoxide (10) [23] (3.0 g, 9.26 mmol) ([h]D=310°
(c=0.57, CHCl3), lit: [h]D=314° (c=0.5)) in 50 ml of
dry THF at −78 °C under Ar, 10.2 mmol of freshly
prepared LDA were added dropwise. The obtained red
solution was stirred at −78 °C for 20 min and then
was poured into a mixture of finely crushed dry ice (4 g,
92 mmol) and THF (20 ml). After warming to r.t., the
reaction mixture was quenched with water (75 ml) and
the organic layer was extracted with Et2O.
The racemic acid 12 was obtained using the same
procedure starting from the racemic 11. The singlet in
1
the H-NMR spectrum at 4.35 ppm corresponding to
the 5FcH of the non-substituted ring of the racemic
acid 12 was splitted in two signals at 4.31 and 4.34 ppm
of the two enantiomers in the presence of S(+)-(9-an-
thryl)-2,2,2-trifluoroethanol as chiral solvating agent.
The same experiment performed on the enantiomeric
enriched acid 11 showed the presence of only one
enantiomer (e.e.\98%)
The water phase was acidified with concentrated
HCl. The resulting acid 11 was filtered, washed with
water and dried (2.5 g, 75% yield). (SFcSS)-11 was
obtained as a single diastereoisomer as was shown by
Starting from a sulphoxide 10 having an enan-
tiomeric excess of 88% ([h]D=280° (c=0.5, CHCl3)
and using the same procedure, the acid 12 was obtained
with an e.e.=86% that was established by analysis of
1
the H- and 13C-NMR analysis. Yellow solid. M.p.=
1
175 °C (Et2O). [h]D=672° (c=0.5, CHCl3). H-NMR
(300 MHz, CDCl3): l 2.36 (s, 3H, CH3), 4.58 (s, 5H,
FcH), 4.65 (t, 1H, J=2.7 Hz, FcH), 4.85 (dd, 1H,
J1=2.7, J2=1.6 Hz, FcH), 5.15 (dd, 1H, J1=2.7,
J2=1.6 Hz, FcH), 7.24 (d, 2H, J=8.3 Hz, ArH), 7.49
(d, 2H, J=8.3 Hz, ArH). 13C-NMR (75.46 MHz,
CDCl3): l 21.36 (CH3), 72.40, 72.52, 73.25, 75.22
(FcCH), 91.46 (FcC), 124.35, 130.27 (ArCH) 139.56,
142.38 (ArC), 169.68 (CO). EIMS; m/z: 368 [M+], 352
[M+−O]. Anal. Found: C, 58.53; H, 4.45. Calc. for
C18H16FeO3S: C, 58.69; H, 4.38%. IR (CCl4, cm−1):
1727 (COOH).
1
its H-NMR spectrum in the presence of Pirkle’s alco-
hol, that showed the two peaks in a 7:93 ratio.
4.7.4. (SFc)-2-(p-Tolylsulphanyl)-ferrocenecarboxylic
acid chloride (13)
Oxalyl chloride (0.17 ml, 2.0 mmol) was added to a
stirred solution of acid (SFc)-12 (0.352 g, 1.0 mmol) in
dry CH2Cl2 (25 ml) under Ar atmosphere at r.t. After
20 min the excess of oxalyl chloride and CH2Cl2 were
removed in vacuo and the residue was dissolved in
Et2O–pentane, filtered and concentrated in vacuo. The
chloride 13 was obtained as a red oil (0.362 g, 0.98
In order to establish the enantiomerical purity of 11,
1
a comparison of its H-NMR spectrum with that of the
racemic 11, obtained using the same procedure starting
from the racemic sulphoxide 10, in the presence of
S(+)-(9-anthryl)-2,2,2-trifluoroethanol as chiral solvat-
ing agent was performed. The singlet at 4.58 ppm
corresponding to the 5FcH of the non-substituted ring
of the racemic acid 11 was splitted in two signals at
4.484 and 4.525 ppm of the two enantiomers. The same
experiment performed on the enantiomerically enriched
1
mmol) in 98% yield. H-NMR (300 MHz, CDCl3): l
2.4 (s, 3H, CH3), 4.44 (s, 5H, FcH), 4.65 (m, 2H, FcH),
5.08 (dd, 1H, J1=2.7, J2=1.6 Hz, FcH), 7.08 (d, 2H,
J=8.2 Hz, ArH), 7.11 (d, 2H, J=8.2 Hz, ArH).
EIMS; m/z: 370 [M+], 334 [M+−HCl], 214 (FcCOH)
(COCl). HRMS Found: 369.9827. Calc. for
C18H15ClFeOS: 369.98815, IR (CCl4, cm−1): 1750.

B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
415
4.7.5. (SFc)-2-(p-Tolylsulphanyl)ferrocenoyl
dimethylphenylsilane (14)
ArH), 7.32 (d, J=7.8 Hz, 2H, ArH), 7.42 (m, 3H,
ArH), 7.66 (m, 2H, ArH). 13C-NMR (75.46 MHz,
CDCl3): l −1.05 (SiMe2), 21.17 (CH3), 70.56, 71.10,
73.16, 74.98 (FcCH), 92.50, 93.26 (FcC), 127.998,
129.50, 129.86, 132.66, 133.94 (ArCH) 132.71, 137.55
(ArC), 283.61 (COSi). HRMS Found: 486.0521. Calc.
for C26H26FeS2Si: 486.0595. EIMS; m/z: 486 [M+], 135
[SiMe2Ph]. The enantiomeric purity was established by
(SFc)-13 (0.37 g, 1.0 mmol) in dry THF (4 ml) was
slowly added at −78 °C under Ar to (dimethyl-
phenylsilyl)copper-cyanocuprate (1.2 mmol) prepared
from CuCN (0.1 g, 1.2 mmol) and dimethylphenylsilyl
lithium (1.2 mmol). The mixture was stirred at −50 °C
for 1 h, then allowed to warm to 0 °C and further
stirred for 1 h. The mixture was quenched with satu-
rated NH4Cl and extracted with Et2O. The organic
layer was dried and concentrated under reduced pres-
sure. Chromatography on silica gel column (n-hexane–
EtOAc, 20:1) gave as the higher Rf fraction, a product
arising from the silylcuprate, as the second Rf fraction
the acylsilane 14 (0.72 g, 58% yield) as red oil. [h]D=
1
comparison of the H-NMR spectra in the presence of
Pirkle’s alcohol of this thioacylsilane with the one
obtained starting from the sulphide 12 with e.e. equal
to 86%. The singlet at 3.88 ppm corresponding to the 5
FcH of the non-substituted ring of the latter acylsilane,
was splitted in two signals at 3.821 and 3.843 of the two
enantiomers in a 8:92 ratio (e.e.=84%). On the con-
trary the enantiomerically pure compound showed only
the signal at 3.843 (e.e.\98%).
1
−683° (c=0.2, CHCl3). H-NMR (300 MHz, CDCl3):
l 0.62 (s, 3H, SiMe), 0.66 (s, 3H, SiMe), 2.34 (s, 3H,
CH3), 3.96 (s, 5H, FcH), 4.18 (dd, 1H, J1=2.7, J2=1.4
Hz, FcH), 4.27 (t, 1H, J=2.7 Hz, FcH), 4.52 (dd, 1H,
J1=2.7, J2=1.4 Hz, FcH), 7.13 (d, J=8.0 Hz, 2H,
ArH), 7.33 (d, J=8.0 Hz, 2H, ArH), 7.44 (m, 3H,
ArH), 7.70 (m, 2H, ArH). 13C-NMR (75.46 MHz,
CDCl3): l −3.245 (SiMe2), 21.14 (CH3), 70.53, 71.19,
71.68, 72.91 (FcCH), 81.53, 87.60 (FcC), 128.11,
129.76, 132.48, 134.13 (ArCH) 131.91, 135.88, 137.45
(ArC), 235.10 (COSi). EIMS; m/z: 470 [M+], 455 [M+
−CH3], 404 [M+−C5H6], 347 [M+−p-Tol-S], 335
[M+−SiMe2Ph], 135 [SiMe2Ph]. HRMS Found:
470.0889. Calc. for C26H26FeOSSi: 470.0823. IR (CCl4,
cm−1): 1577 (COSi).
4.7.7. t-Butyl {[(2-p-tolylsulphanyl)ferrocenyl][dimethyl-
(phenyl)silyl]}methyl sulphide (16)
To a stirred solution of thioacylsilane (SFc)-15 (70
mg, 0.14 mmol) in dry THF (5 ml) at −78 °C and
under Ar, t-BuLi (0.15 mmol, 0.1 ml) was added drop-
wise. The colour of the solution rapidly changed from
blue to yellow. The mixture was concentrated under
1
reduced pressure. The H-NMR spectrum of the mix-
ture showed the presence of two diastereoisomers in a
7.7:1 ratio (d.e.=77%) by integration of well-separated
signals. The crude was chromatographed on deacti-
vated neutral alumina (n-hexane–diethyl ether, 10:1)
affording the two diastereoisomers of 16 in a 68% yield
as a yellow oil. The major isomer was purified by a
second chromatography on preparative TLC.
The enantiomeric purity was established by compari-
1
son of the H-NMR spectra in the presence of Pirkle’s
alcohol of this thioacylsilane with the one obtained
starting from the sulphide 12 with e.e. equal to 86%.
The singlet at 3.96 ppm corresponding to the 5FcH of
the non-substituted ring of the latter acylsilane, was
splitted in two signals at 3.917 and 3.939 of the two
enantiomers in a 92.6:7.4 ratio (e.e.=85%). On the
contrary the enantiomerically pure compound showed
only the signal at 3.917 (e.e.\98%).
1
Major isomer. [h]D= −215° (c=0.52, CHCl3). H-
NMR (300 MHz, CDCl3): l −0.29 (s, 3H, SiMe), 0.10
(s, 3H, SiMe), 1.23 (s, 9H, t-Bu), 2.29 (s, 3H, CH3),
2.99 (s, 1H, CH), 3.90 (bs, 1H, FcH), 4.26 (bt, 1H,
FcH), 4.29 (s, 5H, FcH), 4.49 (bs, 1H, FcH), 7.04 (d,
2H, ArH), 7.18–7.38 (m, 7H, ArH). 13C-NMR (75.46
MHz, CDCl3): l −4.66, −2.46 (SiMe2), 21.02 (CH3),
24.19 (CH), 31.16 (CH3), 44.99 (C), 66.22, 67.42, 70.35,
72.45 (FcCH), 78.53, 83.03 (FcC), 127.18, 128.95,
129.15, 129.40, 134.88 (ArCH) 135.12, 135.87, 137.67
(ArC). EIMS; m/z: 544 [M+], 487 [M+−t-Bu], 135
[SiMe2Ph]. HRMS Found: 544.1343. Calc. for
C30H36FeS2Si: 544.1377.
4.7.6. (SFc)-2-(p-Tolylsulfanyl)thioferrocenoyl
dimethylphenylsilane (15)
To a stirred solution of (SFc)-14 (80 mg, 0.17 mmol)
in 10 ml of dry THF at r.t., 100 mg (0.25 mmol) of
Lawesson’s reagent was added. The red colour of the
solution slowly changed to deep blue. After 45 min, a
TLC analysis (light petroleum–Et2O, 10:1) showed the
disappearance of the starting acylsilane. The solution
was concentrated in vacuo and the residue was chro-
matographed on fluorisil affording 15 (78 mg) in 94%
1
Minor isomer. H-NMR (300 MHz, CDCl3): l 0.62
(s, 3H, SiMe), 0.65 (s, 3H, SiMe), 0.78 (s, 9H, t-Bu),
2.26 (s, 3H, CH3), 3.18 (s, 1H, CH), 4.0 (s, 5H, FcH),
4.42 (m, 2H, FcH), 4.52 (m, 1H, FcH), 7.0–7.4 (m, 9H,
ArH). 13C-NMR (75.46 MHz, CDCl3): l −1.50,
−0.36 (SiMe2), 20.92 (CH3), 25.51 (CH), 30.49 (CH3),
44.1 (C), 66.50, 70.26, 71.33, 72.91 (FcCH), 127.58,
128.39, 128.82, 129.38, 134.40 (ArCH). EIMS; m/z: 568
[M+], 135 [SiMe2Ph].
1
yield as a deep blue oil. H-NMR (300 MHz, CDCl3):
l 0.60 (s, 3H, SiMe), 0.67 (s, 3H, SiMe), 2.35 (s, 3H,
CH3), 3.88 (s, 5H, FcH), 4.42 (t, 1H, J=2.7 Hz, FcH),
4.45 (dd, 1H, J1=2.7, J2=1.4 Hz, FcH), 4.61 (dd, 1H,
J1=2.7, J2=1.4 Hz, FcH), 7.14 (d, J=7.8 Hz, 2H,

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B.F. Bonini et al. / Journal of Organometallic Chemistry 637–639 (2001) 407–417
4.8. (6-Methyl-2-pyridinyl)methyl{[(2-p-tolylsulfanyl)-
ferrocenyl][(dimethyl(phenyl)silyl]}methyl sulphide (17)
tion of well-separated signals. The mixture was then
chromatographed on preparative TLC (n-hexane–
Et2O, 40:1) affording as the first Rf fraction the major
diastereoisomer and as the second Rf fraction the minor
one in an overall yield of 78%. The same reaction has
been performed at −20 °C and afforded in 24 h the
two diastereoisomers in 76% yield in a 4.9:1 ratio
(d.e.=76%).
To a stirred solution of thioacylsilane under Ar (SFc)-
15 (70 mg, 0.14 mmol) in dry THF (5 ml) at −78 °C,
lithium lutidine (0.16 mmol) prepared from freshly
distilled lutidine (1.2 ml) in 12.5 ml of dry THF at
−60 °C and n-BuLi (11 mmol), was added dropwise.
The colour of the solution rapidly changed from blue to
1
Major isomer. [h]D= −236° (c=0.547, CHCl3). H-
1
yellow. The H-NMR spectrum of the mixture showed
NMR (300 MHz, CDCl3): l −0.05 (s, 3H, SiMe), 0.16
(s, 3H, SiMe), 1.34 (s, 3H, CH3), 1.68 (s, 3H, CH3),
2.31 (s, 3H, CH3), 2.71 (dd, J1=J2=16.8 Hz, 2H,
CH2), 3.25 (dd, J1=J2=16.8 Hz, 2H, CH2), 4.18–4.23
(m, 2H, FcH), 4.27 (m, 1H, FcH), 4.28 (s, 5H, FcH),
7.10 (d, 2H, ArH), 7.20 (m, 5H, ArH), 7.4 (d, 2H,
ArH). 13C-NMR (75.46 MHz, CDCl3): l −3.43,
−2.62 (SiMe2), 19.03, 21.03, 21.10 (CH3), 31.64, 40.84
(CH2), 66.86, 68.54, 70.67, 73.87 (FcCH), 81.49, 87.28
(FcC), 126.85, 128.68, 129.45, 129.52, 134.27 (ArCH)
132.91, 135.25, 137.12 (ArC). EIMS; m/z: 568 [M+],
135 [SiMe2Ph]. HRMS Found: 568.1348. Calc. for
C32H36FeS2Si: 568.1377.
the presence of two diastereoisomers in a 3:1 ratio
(d.e.=50%) by integration of well-separated signals.
The mixture was concentrated under reduced pressure
and then chromatographed on deactivated neutral alu-
mina (light petroleum–diethyl ether, 8:1) affording the
two diastereoisomers of 17 as a yellow oil. A further
attempt of separation of the two diastereoisomers on
silica preparative TLC failed.
1H-NMR (300 MHz, CDCl3): l −0.315 (s, 3H,
SiMe major isomer), 0.00 (s, 3H, SiMe major isomer),
0.359 (s, 3H, SiMe minor isomer), 0.411 (s, 3H, SiMe
minor isomer), 2.24 (s, 3H, CH3 minor isomer), 2.28 (s,
3H, CH3 major isomer), 2.48 (s, 3H, CH3 minor iso-
mer), 255 (s, 3H, CH3 major isomer), 3.44 (s, 2H, CH2
minor isomer), 3.48 (s, 2H, CH2 major isomer), 3.73 (s,
1H, CH minor isomer), 3.77 (s, 1H, CH major isomer),
3.94 (s, 5H, FcH minor isomer), 4.01 (m, 1H, FcH
major isomer), 4.13 (m, 1H, FcH minor isomer), 4.23
(m, 1H, FcH minor isomer), 4.27 (s, 5H, FcH major
isomer), 4.31 (m, 1H, FcH major isomer), 4.48 (m, 1H,
FcH minor isomer), 4.50 (m, 1H, FcH major isomer),
6.85-7.74 (10 m, 24H, ArH major and minor isomer),
13C-NMR (75.46 MHz, CDCl3): l −4.97, −3.21
(SiMe major isomer), −2.94, −2.05 (SiMe minor iso-
mer), 20.86, 20.97 (CH major and minor isomer), 27.21,
29.69, 30.31, 30.40, (CH3 major and minor isom), 40.77
(CH2, major isomer), 41.27 (CH2, minor isomer) 66.79,
67.71, 67.81, 70.38, 70.49, 70.988, 71.329, 73.07, (FcCH
major and minor isomer), 120.10, 120.32, 121.12,
121.31, 126.52, 127.18, 127.26, 127.75, 128.43, 128.83,
129.16, 129.30, 134.30, 134.38, 136.40 (ArCH major
and minor isomer). EIMS; m/z: 593 [M+], 487 [M+−
CH2C5H3NCH3], 352 [487−SiMe2Ph], 319 [352−SH],
135 [SiMe2Ph]. HRMS Found: 593.1366. Calc. for
C33H35FeNS2Si: 593.1330.
1
Minor isomer. [h]D= −309° (c=0.336, CHCl3). H-
NMR (300 MHz, CDCl3): l 0.09 (s, 3H, SiMe), 0.34 (s,
3H, SiMe), 1.46 (s, 3H, CH3), 1.53 (s, 3H, CH3), 2.32
(s, 3H, CH3), 2.45 (d, J=17.1 Hz, 1H, HaꢀCH2), 2.96
(m, 3H, HbꢀCH2+CH2), 3.90 (bdd, 1H, FcH), 4.04 (bt,
1H, FcH), 4.11, 3.90 (bdd, 1H, FcH), 4.25 (s, 5H,
FcH), 7.10 (d, 2H, ArH), 7.20 (m, 5H, ArH), 7.4 (m,
2H, ArH). 13C-NMR (75.46 MHz, CDCl3): l −2.92,
−2.46 (SiMe2), 19.09, 20.74, 21.05 (CH3), 31.83, 41.45
(CH2), 66.05, 68.28, 70.64, 72.58 (FcCH), 82.25, 86.23
(FcC), 126.96, 128.72, 129.45, 130.05, 134.24 (ArCH)
134.91, 136.02, 138.25 (ArC). EIMS; m/z: 568 [M+],
135 [SiMe2Ph]. HRMS Found: 568.1352. Calc. for
C32H36FeS2Si: 568.1377.
Acknowledgements
This work has been supported by University of
Bologna (Funds for Selected Research Topics, A.A.
1999–2001) and by the National Project ‘Stereo-
selezione in Sintesi Organica. Metodologie ed Appli-
cazioni 1999–2001’.
4.9. [4,5-Dimethyl-2-(2-p-tolylsulphanylferrocenyl)-
2-dimethyl(phenyl)silyl]3,6-dihydro-2H-thiopyrane (18)
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