Unprecedented effects of the trimethylsilyl group on the reactivity of 3C-silylated silacyclopentenes and their derivatives

Article abstract of DOI:10.1016/S0022-328X(00)00200-X

We have synthesised new 3C-silylated silacyclopentenes from the corresponding 3-trimethylsilyl-1,1-dichloro-1-silacyclopent-3-enes. The presence of two metal centres M (M = Si) in α and β-positions confers an original structure for these new heterocycles. The chemical behaviour of such compounds and their derivatives was studied and compared to the results obtained in the non-substituted silacyclopentane series.

Full text of DOI:10.1016/S0022-328X(00)00200-X

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Journal of Organometallic Chemistry 604 (2000) 141–149
Unprecedented effects of the trimethylsilyl group on the reactivity
of 3C-silylated silacyclopentenes and their derivatives
Rabah Boukherroub a,*, Georges Manuel b
a National Research Council, Steacie Institute for Molecular Sciences, 100 Sussex Dri6e, Ottawa, Ont, Canada, K1A 0R6
b Laboratoire d’He´te´rochimie Fondamentale et Applique´e-UPRESA CNRS No. 5069, Uni6ersite´ Paul-Sabatier, 118 Route de Narbonne,
31062 Toulouse Cedex, France
Received 8 July 1999; accepted 6 March 2000
Abstract
We have synthesised new 3C-silylated silacyclopentenes from the corresponding 3-trimethylsilyl-1,1-dichloro-1-silacyclopent-3-
enes. The presence of two metal centres M (M=Si) in a and b-positions confers an original structure for these new heterocycles.
The chemical behaviour of such compounds and their derivatives was studied and compared to the results obtained in the
non-substituted silacyclopentane series. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Silicon; Synthesis; 3-Trimethylsilyl-3-silacyclopentenes; Vinylsilanes; Epoxysilanes
magnesium in diethyl ether [2]. In fact, hydrosilylation
of the commercially available 1,4-dichlorobut-2-yne
with various silanes and germanes in the presence of
1. Introduction
We have been interested by silacyclopentenes for a
long time. Such compounds have generated a large
interest in both fundamental and applied organometal-
lic chemistry [1]. The chemistry of these heterocycles is
governed mainly by the presence of two reactive sites in
the same molecule: an electron deficient centre M (Si)
and an electron rich carbonꢀcarbon double bond, in
allylic position to the metal M. For example, organo-
lithium compounds (RLi) induce a ring-opening poly-
merisation of these metallacycles resulting from the
nucleophilic attack of R− on the silicon to yield poly(1-
sila-cis-pent-3-enes), precursors of ceramics [1c]. On the
other hand, 3,4-amino-1-silacyclopentanols, prepared in
two steps from corresponding silacyclopentenes, have
shown a biological activity as serotonin antagonists
[1b].
chloroplatinic acid as
a
catalyst yields cis-1,4-
dichlorobut-2-enes (1) bearing corresponding silyl and
germyl groups in 2-position. 2-Substituted cis-1,4-
dichloro-2-butenes (1) react with trichlorosilane in the
presence of triethylamine and catalytic amounts of
cuprous chloride (CuCl) to give a mixture of two
products, 2 and 3. The ratio of the SN2 and SN2%
products varies as a function of the electronegativity of
the groups directly attached to the metal. Reaction of 2,
present in the mixture, with magnesium powder in Et2O
leads to corresponding 3C-substituted 1,1-dichloro-1-
silacyclopent-3-enes (4), in good yields [2].
We have already reported the synthesis of a series of
3C-silylated 1,1-dichloro-1-silacyclopent-3-enes (4) in
two steps, using the reaction of the trichlorosilylation
of allylic chlorides followed by a ring closure with
* Corresponding author. Tel.: +1-613-9900954; fax: +1-
6139914278.
E-mail address: rabah@ned1.sims.nrc.ca (R. Boukherroub).
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00200-X

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R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
In this paper, we wish to report the synthesis and the
reactivity of the 3C-trimethylsilyl-1,1-dimethyl (and 1,1-
diphenyl)-1-silacyclopent-3-enes (5a,b) and their deriva-
reaction occurred when 5 and methane sulfonyl chlo-
ride, in a mixture of CH2Cl2ꢀCH3CN in the presence of
catalytic amounts of cuprous chloride (CuCl), were
heated in a sealed tube at 140°C [5].
tives
6
and
7
with hydrogen halides, lithium
dialkylamides, bromomagnesium dialkylamides, and
Grignard reagents.
Only the starting material was recovered and small
amounts of 8, resulting most likely from a partial
hydrolysis of the methane sulfonyl chloride, generating
HCl. Resulting HCl may induce a protodesilylation
reaction of the 3C-silylated silacycles 5.
In this new 3C-silylated silacyclic series, we will
examine the effect of the trimethylsilyl (TMS) group on
the reactivity of such systems and compare our results
to those reported in the literature in the carbon series
and also to those already reported in the non-silylated
silacyclopentene series.
2.2. 1-Trimethylsilyl-3,3-dimethyl
(diphenyl)-6-oxa-3-silabicyclo[3.1.0]hexane (6a,b)
Oxidation of the carbon–carbon double bond was
achieved using m-chloroperbenzoic acid in diethyl ether
[3a] in high yields.
2. Results and discussion
2.1. 3-Trimethylsilyl-1-silacyclopentenes (5a,b)
3C-silylated 1-silacyclopent-3-enes (5a,b) were pre-
pared from the dichlorosilacyclopentene derivatives (4)
and an excess of the corresponding Grignard reagent
RꢀMgX (R=Me, Ph), respectively in 81 and 90%
yield.
Various examples are reported in the literature con-
cerning the chemical behaviour of a,b-epoxysilanes
[6,7]. For example, such derivatives give aldehydes and
ketones when treated with a solution of sulfuric acid in
methanol (1:10) at 90°C for 10 min [8].
Treatment of 5a,b with concentrated hydrogen
halides (HCl, HBr and HI) leads to the quantitative
formation of 1,1-dimethyl (diphenyl)-1-silacyclopent-3-
enes (8a,b) [3] and trimethylsilyl halides Me3SiX (X=
Cl, Br, I) resulting from a protodesilylation reaction.
This reaction may proceed by the protonation of the
p-electron rich carbon–carbon double bond, followed
by a nucleophilic attack of the counteranion X− on the
trimethylsilyl group, inducing the corresponding
trimethylsilyl halide elimination [4]
The protodesilylation reaction is regioselective. There
was no attack of the X− on the ring-bound silicon (Si).
We did not detect products resulting from a nucle-
ophilic displacement of an intracyclic SiꢀC bond, lead-
ing to a ring-opening reaction.
Ring-opening of a,b-epoxysilanes with different nu-
cleophiles (HBr, MeOH, AcOH) under different condi-
tions has shown that these epoxides undergo
nucleophilic attack at the carbon a to silicon [9,10]. For
example, when the reaction of 1,2-epoxy-1-trimethyl-
silylcyclohexane was carried out with 5% sulfuric acid
In the same conditions as those reported for the
synthesis of allyl and (trimethylsilyl) vinyl sulfones, no

R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
143
in methanol at 0°C, the trans-2-methoxy-2-trimethylsi-
lylcyclohexan-1-ol was obtained in 78% yield:
Besides the steric effect of the trimethylsilyl group, the
presence of a second intracyclic silicon in b-position
induces the ring opening of the silacycle. The nucle-
ophilic reaction of MeOH or AcOH could be ratio-
nalised as a result of a b-effect of silicon.
The same dienic product (9) was isolated when epox-
ides 6 and catalytic amounts of boron trifluoride ether-
ate (BF3, Et2O) [12] were allowed to react in CDCl3 at
room temperature (r.t.) or in dichloromethane at 0°C.
The mechanism of the decomposition of the silyloxirane
(6) is proposed in Scheme 2
Epoxides 6a,b behave differently in acidic media. The
reaction with H2SO4–MeOH (1:10) at −20 or 0°C
yields 2-trimethylsilyl-1,3-butadiene (9) [11] and the cor-
responding siloxanes:
The reaction with acetic acid shows a difference with
the non-substituted analogue. In fact, 6-oxa-3,3-
dimethyl(or diphenyl)-3-silabicyclo[3.1.0]hexanes when
heated at 80°C in neat acetic acid (AcOH) gave the
corresponding silacyclic acetoxy alcohol (10) as a result
of the ring-opening of the oxirane bridge [1b]:
The first step corresponds to the complexation of
the Lewis acid (BF3) by oxygen. The subsequent
heterolytic cleavage of a siliconꢀcarbon bond leads to
the formation of a positive charge in a-position to the
We assume that the mechanism of this reaction is
similar to the one reported by Stork et al. [8] involving
methanolic solution of H2SO4 and a,b-epoxysilanes.
The first step corresponds to the protonation of the
oxygen of the oxirane ring. The presence of the
trimethylsilyl group facilitates nucleophilic displacement
of the silicon–carbon bond a to silicon and thus favours
the formation of a carbonium ion in a b-position to the
intracyclic silicon. Nucleophilic attack of MeOH on
silicon in the b-position leads to the ring-opening
product. The protonation of the hydroxyl group of the
intermediate alcohol, in the acidic media, followed by a
second nucleophilic attack of MeOH on the methoxysi-
lyl group yields 2-trimethylsilyl-1,3-butadiene (9) and
the corresponding dialkyldimethoxysilanes. Nucleo-
philic displacement occurs at the silicon bearing a
methoxy group rather than at the TMS group because
of the electron deficiency at the first silyl group (Scheme
1).
trimethylsilyl group. Nucleophilic attack of the electron
rich oxygen on the intracyclic silicon, in b-position,
gives the intermediate resulting from the ring-opening
reaction of the silacycle with regeneration of BF3 and
formation of silaoxetane. Thermal decomposition of the
silaoxetane intermediate leads to 2-trimethylsilyl-1,3-bu-
tadiene (9) and silanones. Cyclooligomerisation of the
silanones gives corresponding siloxanes. Similarly, 1,3-
butadiene and corresponding siloxanes were obtained
when unsubstituted oxasilabicyclo-[3.1.0]hexanes were
reacted with catalytic amounts of boron trifluoride.
An alternative mechanism in which free fluoride an-
ion (F−) attacks the ring-bound silicon was suggested
by Weber et al. [13]. BF3 may induce complexation
rather than decomposition because BF3 forms stable
complexes with ethers. Nucleophilic attack by F− is less
probable in this case even though the final products are
the same.

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R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
The same behaviour was observed when 3,3-dimethyl
There is no spectroscopic evidence (1H-NMR, IR)
(and 3,3 - diphenyl) - 6 - oxa - 3 - silabicyclo[3.1.0]hexanes
were reacted, respectively with N-benzyltriphenylphos-
phinimine (Ph3P+ꢀN−ꢀCH2ꢀPh) [14] and tetra-n-butyl-
ammonium bromide [15].
for the formation of the isomeric silylenol ether (11)
resulting from
a b-cleavage of a carbonꢀoxygen
bond induced by the strong Lewis acid BF3 followed
by a migration of the trimethylsilyl group from
Scheme 1.
Scheme 2.

R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
145
carbon to an a-oxygen as reported for a,b-epoxysilanes
[12].
The reaction is regioselective. The nucleophilic dis-
placement occurs at the SiꢀC bond a to TMS group.
There was no spectroscopic evidence for the formation
of a tertiary alcohol resulting from the cleavage of the
silicon–carbon bond b to the TMS group. The high
stereospecificity of this reaction suggests that the
trimethylsilyl group facilitates displacement a to silicon
and a b-elimination process due to the presence of the
intracyclic silicon.
Addition of one equivalent of bromomagnesium di-
ethylamide, Et2NMgBr to the cyclic a,b-epoxysilanes
(6) gave the silacyclopentenol (13) in contrast to the
unsubstituted isologue, which afforded the correspond-
ing a, b-aminoalcohol (12) [1b]:
2.3. 3-Trimethylsilyl-1,1-dimethyl(diphenyl)-
1-silacyclopentan-4-ol (7a,b)
Reduction of the epoxides 6a,b with lithium alu-
minium hydride in diethyl ether produced the sec-
ondary alcohols 7a,b. This is in agreement with the
previous observations regarding the lithium aluminium
hydride reduction of a,b-epoxysilanes. The mechanism
of this reaction is elucidated in the literature [18].
Reduction of the 3C-methylated epoxides offers the
corresponding tertiary alcohols [19]. These epoxides
undergo reduction with hydride attack at the more
sterically accessible carbon in contrast to the 3-silyl-
ated oxiranes where the nucleophilic displacement
occurs at the carbon bearing the bulky trimethylsilyl
group. This result is consistent with the previous ob-
servations concerning the nucleophilic attack at the
a-carbon.
Same results were obtained when the reaction was
carried out in the presence of lithium diethylamide,
Et2NLi and HX (X=Cl, Br). This regiochemistry of
the silylated epoxide is enhanced by the presence of the
trimethylsilyl group. Abstraction of the hydrogen in the
a-position to the intracyclic metal by relatively weak
bases (X−=Cl−, Br−) may be attributed to the in-
crease of the acidity of this atom. On the other hand,
the steric hindrance of the trimethylsilyl group may
direct the reaction in the observed path. Both
R2NMgBr and HX (X=Cl, Br) open the epoxide to
give the corresponding amino alcohols and halohydrins,
respectively, when they are reacted with the unsubsti-
tuted 6-oxa-3-silabicyclo[3.1.0]hexanes (R%=H) 1b, 16.
Hudrlik et al. [17] have shown that an a,b-epoxysi-
lane could be considered as a masked aldehyde or
ketone and gave an example illustrating this hypothesis
by reacting these epoxides with Grignard reagents. Cor-
responding b-alcohols are isolated:
When 1-trimethylsilyl-3,3-diphenyl-6-oxa-3-silabicy-
clo[3.1.0]hexane (6b) and an ethereal solution of
methylmagnesium iodide were refluxed for 1 h, only
linear k-ethylenic silacompound (14b) was formed
quantitatively. The reaction is similar in the unsubsti-
tuted epoxide series:
Treatment of alcohols 7a,b with hydrogen halides
HX (X=Cl, Br, I) or phosphorus trichloride gave
the corresponding 1,1-dimethyl(diphenyl)-silacyclo-

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R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
pent-3-enes (8a,b) and Me3SiX (X=Cl, Br, I) or
HOPCl2:
The first reaction corresponds to the protonation of
the alcohol function or to the nucleophilic substitution
at the phosphorus atom. The counteranion X− attacks
the electron deficient metal (Si) in the b-position. In the
case of the non-substituted alcohol, nucleophilic attack
occurs at the intracyclic silicon to give the ring-opening
product 15 after hydrolysis. With the substituted alco-
hol (R%ꢁSiMe3), the SN2% reaction takes place at the
trimethylsilyl group resulting in an anti-elimination re-
action of chlorotrimethylsilane (TMSCl) and formation
of the corresponding silacyclopentene (8a,b).
Bruker AC 80 and 250 MHz spectrometer in deuteri-
1
ochloroform (CDCl3). The H and 13C chemical shifts
(l) are given in ppm and referenced relative to Me4Si.
The coupling constants are given in Hz. Melting points
were determined in evacuated capillaries with a Buchi–
Tottoli apparatus. IR spectra were recorded as thin
films on a Perkin–Elmer System Series 1600 FT-IR
spectrometer. Low-resolution mass spectra were deter-
mined by GC–MS using a Hewlett–Packard 5890 Serie
II gas chromatograph equipped with a HP/MS 5989A
mass selective detector. An ionising voltage of 70 eV
was used (mass spectra are reported in mass-to-charge
units, m/z, with ion identity and peak intensities rela-
tive to the base peak in parentheses).
4.1. Synthesis of 3-trimethylsilyl-1,1-dimethyl-
1-silacyclopent-3-ene (5a)
3. Conclusions
To a solution of methyl magnesium iodide MeMgI
(prepared from 4.5 g of magnesium turnings and 25 g
of methyl iodide in 100 ml of diethyl ether), was added
dropwise, under vigorous stirring, 13.1 g (58.24 mmol)
of 3-trimethylsilyl-1,1-dichlorosilacyclopent-3-ene (4a)
in 60 ml of Et2O. After refluxing for 21 h, the mixture
was cooled to 0°C (ice bath) and hydrolysed with 30 ml
of a saturated ammonium chloride aqueous solution,
and washed with water (2×50 ml). The aqueous layer
was extracted with pentane.
We have shown that the chemical properties of the
3-trimethylsilyl silacyclopentenes (5) follow the trends
of simple vinylsilanes while the presence of
trimethylsilyl group on the oxiranes (6) and alcohols (7)
modified the chemical behaviour of such series. These
results underline the electronic and steric properties of
the trimethylsilyl group in the b-position of the silicon
atom present in the heterocycle.
a
Further investigations on the scope of these reactions
are in progress.
The combined organic layers were dried over sodium
sulphate and the solvents were removed in vacuo. 8.68
g of the product 5a were isolated after distillation of the
crude liquid. B.p: 73°C/20 mmHg. Yield: 81%. Anal.
Calc. For C9H20Si2: C, 58.62; H, 10.93. Found: C,
58.67; H, 10.87%.
4. Experimental
All experiments were carried out in flame-dried glass-
ware under an atmosphere of argon. Diethyl ether and
pentane were distilled freshly from sodium–benzophe-
none ketyl prior to use. Methyl iodide, bromobenzene
and diethylamine were obtained from Aldrich Chemical
Co., m-chloroperbenzoic acid (85%) was purchased
from Air Liquide and used without additional purifica-
tion. All NMR spectra were recorded at 25°C on a
IR: 2994, 2955, 2898 (CꢀH stretch), 1577 (CꢁC),
1398, 1247, 1146, 1096, 1002, 957, 837, 787, 749, 724,
690 cm−1
.

R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
147
1H-NMR l: 0.05 (s, 9H, Me3Si), 0.15 (s, 6H, Me2Si),
1.33 (m, 4H, H2, H3, H4, H5), 6.15 (m, 1H, H1).
13C-NMR l: −2.13 (Me2Si), −1.96 (Me3Si), 19.98
(C2), 20.78 (C5), 139.61 (C4), 144.89 (C3). GC–MS m/e
(relative intensity): 184 (25) (M)+, 169 (71) (MꢀMe)+,
141 (23) (MꢀMeSi)+, 111 (4) (MꢀMe3Si)+, 96 (10)
(MꢀMe4Si)+, 73 (100) (Me3Si)+, 59 (38) (Me2SiH)+, 58
(20) (Me2Si)+, 43 (51) (MeSi)+, 29 (13) (C2H5)+.
1249, 1173, 1121, 1083, 988, 974, 897, 838, 747, 734,
704, 648, 636 cm−1 1H-NMR l: −0.00 (s, 9H,
.
Me3Si), 0.05 (s, 3H, Me1Si), 0.07 (s, 3H, Me2Si), 0.94
(ddd, J(H1H2)=15.7 Hz; 4J(H1H3)=4J(H2H3)=0.6
Hz, 2H, H1, H2), 0.99 (ddd, J(H4H5)=15.7 Hz;
3J(H4H3)=3J(H5H3)=2.0 Hz, 2H, H4, H5), 3.27 (td,
4
3J(H3H4)=3J(H3H5)=2.0 Hz; J(H3H1)=4J(H3H2)=
0.6 Hz, 1H, H3). 13C-NMR l: −3.64 (Me3Si), −1.27
(Me1Si), 0.49 (Me2Si), 16.76 (C2), 17.09 (C4), 61.67
(C1), 61.80 (C5).
4.2. Synthesis of 3-trimethylsilyl-1,1-diphenyl-
1-silacyclopent-3-ene (5b)
GC–MS m/e (relative intensity): 200 (2) (M)+, 185
(15) (MꢀMe)+, 157 (17) (MꢀSiMe)+, 147 (63)
(Me3SiOSiMe2)+, 117 (17) (Me3SiC2H4)+, 101 (39)
(Me3SiCO)+, 85 (12) (Me2SiC2H3)+, 73 (100) (Me3Si)+,
59 (54) (Me2SiH)+, 58 (24) (Me2Si)+, 45 (73)
(MeSiH2)+, 43 (62) (MeSi)+, 29 (21) (HSi)+.
In a 500 ml two-neck round-bottom flask, containing
an ethereal solution of phenylmagnesium bromide (pre-
pared from 34.6 g of bromobenzene and 11.0 g of
magnesium turnings in 100 ml of ether), were added at
0°C (ice bath), 15.69 g (69.65 mmol) of 3-trimethylsilyl-
1,1-dichloro-1-silacyclopent-3-ene (4b) in 100 ml of di-
ethyl ether. The flask was allowed to warm up
gradually to r.t. and then the mixture was refluxed for
48 h. After hydrolysis and the usual work up, 19.24 g of
the product were distilled as a colourless liquid. Bp:
130°C/0.1 mmHg. Yield: 90%. IR: 3067, 3049, 2997,
2953, 2894, 1953, 1889, 1818, 1765, 1578 (CꢁC), 1485,
1427, 1391, 1303, 1259, 1246, 1188, 1145, 1065, 1028,
4.4. 1-Trimethylsilyl-3,3-diphenyl-6-oxa-3-
silabicyclo[3.1.0]hexane (6b)
1
1002, 955, 909, 836, 811, 770, 725, 697 cm−1. H-NMR
l: 0.37 (s, 9H, Me3Si), 2.16 (m, 4H, H2, H3, H4, H5),
6.56 (m, 1H, H1), 7.51–7.86 (m, 10H, Ph2Si). 13C-NMR
l: −1.58 (Me3Si), 19.34 (C2), 20.21 (C5), 127.45,
127.53, 128.23, 129.05, 129.72, 135.03, 136.38 (aromat-
ics), 139.75 (C4), 145.49 (C3). GC–MS m/e (relative
intensity): 308 (24) (M)+, 293 (32) (MꢀMe)+, 265 (3)
(MꢀMeSi)+, 231 (6) (MꢀC6H5)+, 197 (26) (Ph2SiMe)+,
181 (31) (197-CH4)+, 135 (38) (PhSiMe2)+, 105 (67)
(PhSi)+, 77 (8) (C6H5)+, 73 (100) (Me3Si)+, 59 (44)
(Me2SiH)+, 58 (28) (Me2Si)+, 53 (35) (C4H5)+, 43 (73)
(MeSi)+.
As previously, epoxidation of 2.0 g (6.48 mmol)
ethylenic heterocycle (5b) gave after recrystallisation in
pentane, 2.0 g of white crystals of 6b. M.p.: 58°C.
Yield: 95%. IR: 3069, 3061, 2998, 2958, 2898, 1954,
1881, 1428, 1393, 1358, 1250, 1189, 1173, 1114, 1083,
1
987, 889, 841, 784, 726, 698, 641 cm−1. H-NMR l:
0.10 (s, 9H, Me3Si), 1.48 (ddd, J(H1H2)=15.9 Hz;
4J(H1H3) c 4J(H2H3)=1.6 Hz, 2H, H1, H2), 1.68
3
3
(ddd, J(H4H5)=15.9 Hz; J(H4H3) c J(H5H3)=2.2
Hz, 2H, H4, H5), 3.49 (td, J(H3H4)=3J(H3H5)=2.2
3
Hz; J(H3H1)=4J(H3H2)=1.6 Hz, 1H, H3). 13C-NMR
4
l: −3.45 (Me3Si), 16.29 (C2), 16.41 (C4), 61.49 (C1),
61.59 (C5), 127.34, 128.12, 128.85, 129.54, 134.92,
135.52, 135.86, 136.13 (aromatic carbons). MS m/e
(relative intensity): 324 (7) (M)+, 309 (8) (MꢀMeSi)+,
281 (10) (Ph2SiCH2CSiMe3)+, 271 (50) (Ph2SiOSiMe)+,
225 (46) (Ph2SiCH2CHO)+, 193 (100) (271-C6H6)+, 183
(76) (Ph2SiH)+, 182 (9) (Ph2Si)+, 181 (38) (271-
Me3SiOH)+, 135 (37) (PhSiMe2)+, 121 (14) (Ph-
SiHMe)+, 105 (47) (PhSi)+, 77 (13) (C6H5)+, 73 (58)
(Me3Si)+, 53 (13) (C4H5)+, 45 (41) (MeSiH2)+, 43 (16)
(MeSi)+, 29 (5) (HSi)+.
4.3. 1-Trimethylsilyl-3,3-dimethyl-6-oxa-3-silabicyclo
[3.1.0]hexane (6a)
In a 250 ml two-neck round-bottom flask, were
placed 5.1 g (25 mmol) of m-chloroperbenzoic acid
(85%) and 50 ml of diethyl ether. The flask was cooled
to 0°C and an ethereal solution of the metallacyclopen-
tene (5a) [4.1 g (22 mmol) in 30 ml of ether)] was added
dropwise with stirring. The flask was left to warm up
gradually to r.t. and kept at this temperature for an-
other 12 h. The mixture was then treated with 50 ml of
a 10% sodium hydroxide aqueous solution and washed
with water (2×50 ml). The aqueous layers were ex-
tracted with Et2O. The combined organic layers were
dried over Na2SO4 and the solvents were removed
under pressure. Distillation of the residual liquid gave
3.71 g of 6a as a colourless liquid. B.p.: 83°C/18
mmHg. Yield: 83%. IR: 2956, 2926, 2896, 1398, 1358,
4.5. 3-Trimethylsilyl-1,1-dimethyl-1-silacyclopent-2-
ene-4-ol (13a)
In a 100 ml two-neck round-bottom flask, was placed
a solution of Et2NLi in pentane, prepared by addition
of 10 ml of n-BuLi (1.6 M in hexanes) to an excess of
diethylamine (1.3 g) in 20 ml of pentane. To this

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R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
solution, was added dropwise using a syringe, 2.45 g
(12.22 mmol) of 6a solution in 15 ml of ether at 0°C.
The flask was allowed to warm up to r.t. and kept at
this temperature for an additional 12 h, hydrolysed
with a saturated aqueous solution of NH4Cl and
washed with water (2×25 ml). The aqueous layers
were extracted with ether. The organic layers were
combined, dried over Na2SO4 and the solvents were
removed under pressure. Distillation of the residual
liquid gave 1.18 g of the allylic alcohol 12a as a
colourless liquid. Bp: 42°C/0.1 mmHg, Yield: 48%.
Anal. Calc. For C9H20OSi2: C, 53.93; H, 10.06. Found:
C, 54.06; H, 10.37%. IR: 3601 (free OH), 3404 (associ-
ated OH), 2954, 2898, 1405, 1317, 1247, 1221, 1142,
1044, 910, 874, 843, 801, 751, 735, 691, 669, 642, 618
5.6 Hz, 3J(H2H4)=7.1 Hz, 4J(H2H1)=1.7 Hz, 1H,
4
H2), 6.79 (d, J(H1H2)=1.7 Hz, 1H, H1). 13C-NMR l:
−0.68 (Me3Si), 23.56 (C5), 80.07 (C4), 128.11, 129.73,
129.78, 130.12, 134.78, 135.04, 135.51 (aromatics).
4.7. 4-Diphenyl(methyl)silyl-2-trimethylsilylbut-1-ene
3-ol (14b)
To an ethereal solution of MeMgI [prepared from 1.5
g (10 mmol) of iodomethane and 0.5 g (21 mmol) of
magnesium turnings in 10 ml of Et2O], were added
dropwise 0.65g (2 mmol) of epoxide 6b in 5 ml of ether.
The solution was refluxed for 1 h and then hydrolysed
at r.t. with a saturated aqueous solution of NH4Cl.
After the usual work up, the crude product was purified
by chromatography on silica gel using a mixture of
pentane–ether=95:5 as eluent to yield 0.60 g. Yield:
88%.
cm−1
.
1H-NMR l: 0.08 (s, 3H, Me1Si), 0.13 (s, 9H, Me3Si),
0.18 (s, 3H, Me2Si), 0.63 (dd, J(H3H4)=14.5 Hz,
3J(H3H2)=5.7 Hz, 1H, H3), 1.39 (dd, J(H4H3)=14.5
1H-NMR l: 0.11 (s, 9H, Me3Si), 0.14 (s, 3H, MeSi),
1.49 (d, J(H4H3)=7.0 Hz, 2H4), 4.52 (td, J(H3H4)=
7.0 Hz, 4J(H3H1)=1.0 Hz, 4J(H4H2)=1.3 Hz, 1H,
H3), 5.34 (dd, J(H1H2)=2.4 Hz, 4J(H1H3)=1.0 Hz,
1H, H1), 5.72 (dd, J(H2H1)=2.4 Hz, 4J(H2H3)=1.3
Hz, 1H, H2). 13C-NMR l: −0.21 (MeSi), 1.13 (Me3Si),
24.56 (C4), 74.12 (C3), 122.73 (C1), 127.95, 127.97,
129.29, 134.63, 134.68, 137.21, 137.49 (aromatic car-
bons), 157.78 (C2). GC–MS m/e (relative intensity):
322 (1) (MꢀH2O)+, 214 (1) (Ph2MeSiOH)+, 211 (4)
(Ph2MeSiCH2)+, 210 (9) (Ph2SiCO)+, 199 (40)
(Ph2SiOH)+, 198 (22) (Ph2SiO)+, 197 (100) (Ph2SiMe)+,
181 (9) (197-CH4)+, 105 (15) (PhSi)+, 77 (5) (C6H5)+,
73 (36) (Me3Si)+, 53 (6) (C4H5)+, 43 (11) (MeSi)+.
3
3
3
Hz, J(H4H3)=7.2 Hz, 1H, H4), 1.58 (m, 1H, OH),
4.87 (ddd, 3J(H2H4)=7.2 Hz; 3J(H2H3)=5.7 Hz,
4
4J(H2H1)=1.7 Hz, 1H, H2), 6.6 (d, J(H1H2)=1.7 Hz,
1H, H1). 13C-NMR l: −1.89 (Me1Si), −0.82 (Me3Si),
−0.61 (Me2Si), 24.50 (C5), 79.84 (C4), 144.40 (C2),
173.42 (C3). GC–MS m/e (relative intensity): 185 (11)
(MꢀMe)+, 183 (14) (M+1-H2O)+, 169 (7) (M+1-
MeOH)+, 157 (29) (Me2SiCHꢁCHSiMe3)+, 141 (17)
(MꢀMe2SiH)+, 110 (29) (Me2SiC4H4)+, 85 (14)
(MeSiC4H4)+, 75 (66) (Me2SiOH)+, 73 (100) (Me3Si)+,
59 (18) (Me2SiH)+, 58 (11) (Me2Si)+, 45 (69)
(MeSiH2)+, 43 (59) (MeSi)+, 29 (15) (HSi)+.
4.6. 3-Trimethylsilyl-1,1-diphenyl-1-silacyclopent-2-ene
4-ol (13b)
4.8. 3-Trimethylsilyl-1,1-dimethyl-1-silacyclopentan-
4-ol (7a)
As previously, 0.53 g (1.63 mmol) of epoxide 6b in 5
ml of diethyl ether were added slowly at 0°C to a
solution of Et2NLi in pentane [prepared by addition of
1.6 ml (2.54 mmol) of n-BuLi (1.6 M in hexanes) to 0.3
g (4.1 mmol) of Et2NH in 5 ml of pentane]. The flask
was allowed to warm up to r.t. with stirring and kept at
this temperature for 12 h. After the usual work up and
purification of the crude product by chromatography
on silica gel (50 g of SiO2) using a mixture of pentane–
Et2O (95/5) as eluent, 0.10 g of the product were
In a 50 ml two-neck round-bottom flask, were placed
0.32 g (excess) of LiAlH4 suspension in 10 ml of diethyl
ether. To this solution, were added, via a syringe, 0.74
g (3.70 mmol) of epoxide 6a solution in 5 ml of ether
with stirring. The mixture was refluxed for 3 h, hy-
drolysed at r.t. with 0.5 ml of water. The white precip-
itate (aluminium salts) was filtered over a glass fritte
and washed with diethyl ether. The solvents were re-
moved in vacuo and the residual liquid was purified by
chromatography on silica gel using a mixture of pen-
tane–ether=90:10 as eluent, to give 0.66 g of 7a as a
colourless liquid. Yield: 89%. Anal. Calc. for
C9H22OSi2:
1
isolated as a colourless liquid. Yield: 19%. H-NMR l:
0.26 (s, 9H, Me3Si), 1.22 (dd, J(H3H4)=14.8 Hz;
3J(H3H2)=5.6 Hz, 1H, H3), 1.96 (dd, J(H4H3)=14.8
Hz; 3J(H4H2)=7.1 Hz, 1H, H4), 5.15 (ddd, 3J(H2H3)=

R. Boukherroub, G. Manuel / Journal of Organometallic Chemistry 604 (2000) 141–149
149
W.P. Weber, R. Boukherroub, Main Group Met. Chem. 19 (5)
(1996) 263, and the references cited therein.
[2] (a) R. Boukherroub, G. Manuel, W.P. Weber, J. Organomet.
Chem. 444 (1993) 37. (b) R. Boukherroub, G. Manuel, J.
Organomet. Chem. 460 (1993) 155. (c) R. Boukherroub, G.
Manuel, Main Group Met. Chem. 17 (5) (1994) 319.
[3] (a) G. Manuel, P. Mazerolles, J.C. Florence, C. R. Acad. Sci.
Paris, ser. C 269 (1969) 1553. (b) G. Manuel, P. Mazerolles, J.C.
Florence, J. Organomet. Chem. 30 (1971) 5. (c) G. Manuel, P.
Mazerolles, M. Lesbre, J. P. Pradel, J. Organomet. Chem. 61
(1973) 147. (d) G. Manuel, P. Mazerolles, G. Cauquy, Syn.
Inorg. Metal. Org. Chem. 4 (1974) 133. (e) G. Manuel, W.P.
Weber, in: R.B. King, J.J. Eisch (Eds.), Organometallic Synthe-
ses, vol. 4, Elsevier, Amsterdam, 1988, p. 477.
C, 53.39; H, 10.95. Found: C, 53.60; H, 11.14%. IR:
3623 (free OH), 3483 (associated OH), 2952, 2898,
1403, 1319, 1247, 1142, 1104, 1071, 1001, 986, 939, 909,
1
883, 837, 736, 699, 661, 644 cm−1. H-NMR l: 0.05 (s,
9H, Me3Si), 0.08 (s, 3H, Me1Si), 0.20 (s, 3H, Me2Si),
0.65 (m, 1H, OH), 1.00 (m, 5H, H1, H2, H3, H5, H6),
4.59 (m, 1H, H4). 13C-NMR l: −1.79 (Me3Si), −1.51
(Me1Si), −0.43 (Me2Si), 9.89 (C2), 27.00 (C5), 34.42
(C3), 75.87 (C4).
[4] I. Fleming, J. Dunogue`s, R. Smithers, Org. React. (NY) 37
(1989) 57.
[5] J.P. Pillot, J. Dunogue`s, R. Calas, Synthesis (1977) 469.
[6] (a) T.H. Chan, T. Fleming, Acc. Chem. Res. 10 (1977) 442. (b)
T.H. Chan, T. Fleming, Synthesis (1979) 761. (c) E.W. Colvin,
Silicon in Organic Synthesis, Butterworths, London, 1981. (d) I.
Fleming, in: D.H.R. Barton, W.D. Ollis (Eds.), Comprehensive
Organic Chemistry, vol. 3, Pergamon Press, Oxford, 1979. (e)
W.P. Weber, Silicon Reagents in Organic Synthesis, Springer,
Berlin, 1983.
4.9. 3-Trimethylsilyl-1,1-diphenyl-1-silacyclopentan-
4-ol (7b)
[7] I. Fleming, A. Barbero, D. Walter, Chem. Rev. 97 (1997) 2063.
[8] G. Stork, E. Colvin, J. Am. Chem. Soc. 93 (1971) 2080.
[9] A.P. Davis, G.J. Hughes, P.R. Lowndes, C.M. Robbins, E.J.
Thomas, G.H. Whitham, J. Chem. Soc. Perkin Trans. 1 (1981)
1934.
[10] P.F. Hudrlik, A.M. Hudrlik, R.J. Rona, R.J. Misra, G.P. With-
ers, J. Am. Chem. Soc. 99 (1977) 1993.
[11] K. Takenaka, T. Hattori, A. Hirao, S. Nakahama, Macro-
molecules 22 (1989) 1563.
[12] (a) G. Nagendrappa, Tetrahedron 38 (1982) 2429. (b) I. Fleming,
T.W. Newton, J. Chem. Soc. Perkin Trans. 1 (1984) 119.
[13] R. Damrauer, W.P. Weber, G. Manuel, Chem. Lett. (1987) 235.
[14] A. Baceiredo, C.D. Juengst, G. Manuel, W.P. Weber, Chem.
Lett. (1987) 237.
As above, from 1.34 g (4.13 mmol) of epoxide 6b, we
distilled after reduction, 1.01 g of the alcohol 7b. Bp:
140°C/0.05 mmHg. Yield: 75%. IR: 3582 (free OH),
3458 (associated OH), 3067, 3948, 3019, 2949, 2901,
1486, 1427, 1403, 1317, 1245, 1141, 1113, 1073, 998,
1
938, 879, 638, 810, 786, 728, 698, 624 cm−1. H-NMR
l: 0.13 (s, 9H, Me3Si), 1.14 (m, 5H, H1, H2, H3, H5,
H6), 1.20 (m, 1H, OH), 4.81 (m, 1H, H4), 7.3–7.8 (m,
10H, Ph2Si). 13C-NMR l: −1.67 (Me3Si), 9.37 (C2),
26.13 (C5), 35.24 (C3), 75.73 (C4), 127.91, 128.02,
129.33, 134.90, 135.22, 136.71 (aromatic carbons). MS
m/e (relative intensity): 311 (1) (MꢀMe)+, 282 (1)
(Ph2SiCH2CHSiMe3)+, 236 (78) (MꢀMe3SiOH)+, 225
(15) (Ph2SiCH2CHO)+, 199 (33) (Ph2SiOH)+, 183 (22)
(Ph2SiH)+, 182 (33) (Ph2Si)+, 181 (49) (199-H2O)+, 158
(100) (MꢀMe3SiOHꢀC6H6)+, 135 (16) (PhSiCH2O)+,
121 (10) (PhSiOH)+, 105 (24) (PhSi)+, 77 (10) (C6H5)+,
73 (23) (Me3Si)+, 53 (5) (C4H5)+.
[15] Y.T. Park, G. Manuel, R. Bau, D. Zhao, W.P. Weber,
Organometallics 10 (1991) 1586.
[16] (a) G. Manuel, G. Bertrand, F. El Anba, Organometallics 2
(1983) 391. (b) G. Manuel, G. Bertrand, W.P. Weber, S.A.
Kazoura, Organometallics 3 (1984) 1340. (c) W.P. Weber, S.A.
Kazoura, G. Manuel, G. Bertrand, Ellis Horwood, New York,
1985, 99.
[17] P.F. Hudrlik, A.M. Hudrlik, R.N. Misra, D. Paterson, G.P.
Withers, A.K. Kulkarni, J. Org. Chem. 45 (1980) 4444.
[18] (a) J.J. Eisch, J.E. Galle, J. Org. Chem. 41 (1976) 2615. (b) J.J.
Eisch, J.T. Trainor, J. Am. Chem. Soc. 85 (1963) 2870. (c) W.E.
Fristad, T.R. Bailey, L.A. Paquette, J. Org. Chem. 45 (1980)
3028.
References
[1] (a) G. Manuel, R. Boukherroub, J. Organomet. Chem. 447
(1993) 167. (b) R. Boukherroub, G. Manuel, S. Mignani, D.
Damour, J. Organomet. Chem. 484 (1994) 119. (c) G. Manuel,
[19] (a) G. Manuel, P. Mazerolles, J.C. Florence, C. R. Acad. Sci.
Paris 269 (1969) 1553. (b) G. Manuel, P. Mazerolles, J.C.
Florence, J. Organomet. Chem. 30 (1971) 5.
.