Synthesis of 2-methylidene-1-silacyclohexanes from 2,6-dibromohex-1-ene and polyhalosilanes

Article abstract of DOI:10.1016/j.jorganchem.2006.08.061

Various 2-methylidene-1-silacyclohexanes were prepared by straightforward syntheses from readily available polychloro- or polyfluorosilanes, magnesium and 2,6-dibromohex-1-ene using Barbier-type conditions or a previously synthesized Grignard reagent. Good yields were obtained considering the low stability of the products in the reaction conditions.

Full text of DOI:10.1016/j.jorganchem.2006.08.061

Journal of Organometallic Chemistry 691 (2006) 5531–5539
www.elsevier.com/locate/jorganchem
Synthesis of 2-methylidene-1-silacyclohexanes from
2,6-dibromohex-1-ene and polyhalosilanes
1
*
´
´
Silvia Dıez-Gonzalez , Luis Blanco
`
´ ´ ´ ´
Laboratoire de Synthese Organique et Methodologie, Institut de Chimie Moleculaire et des Materiaux d’Orsay (Associe au CNRS),
ˆ
Bat. 420, Univ. Paris-Sud, 91405 Orsay, France
Received 30 June 2006; received in revised form 17 August 2006; accepted 17 August 2006
Available online 30 August 2006
Abstract
Various 2-methylidene-1-silacyclohexanes were prepared by straightforward syntheses from readily available polychloro- or polyflu-
orosilanes, magnesium and 2,6-dibromohex-1-ene using Barbier-type conditions or a previously synthesized Grignard reagent. Good
yields were obtained considering the low stability of the products in the reaction conditions.
Ó 2006 Elsevier B.V. All rights reserved.
Keywords: Vinylsilane; Fluorosilane; Barbier-type conditions; Organodimetallic reagent; Cyclization
1. Introduction
2-Methylidene-1-silacyclohexanes with diverse substitu-
ents on the olefin or on the cycle have also been prepared
by similar methods [12,13], beside ene reaction from isop-
ropenylsilanes bearing a 3-oxopropyl chain [14] and ring
expansion of a silacyclobutane in the presence of an allene
[15,16]. To the best of our knowledge, the only reported 2-
methylidene-1-silacyclohexane without any substituent on
the carbon atoms was prepared by a Wittig reaction with
a 2-silacyclohexan-1-one [17]. Such acylsilane can be pre-
pared from a silacyclohexene by a sequence hydrobora-
tion/oxidative cleavage/oxidation [18] or by hydrolysis of
the corresponding dithiane in the presence of mercury salts
[19]. Both approaches are time-consuming and require the
use of unstable or toxic reagents.
Reaction of a dihalogenated compound with a metal in
the presence of a dihalosilane or reaction of a dihalosilane
with an organodimetallic reagent would be more conver-
gent approaches to a silacycloalkane. Yet very few
alkylidenesilacycloalkanes were prepared by such methods
[20–22]. Herein, we report the straightforward preparation
of 2-methylidene-1-silacyclohexanes 7 from di- or trihalo-
silanes and 2,6-dibromohex-1-ene 4 using Barbier-type
conditions or employing a preformed organodimetallic
reagent (Scheme 1).
The synthesis of silacycloalkanes has attracted much
attention [1]. We were especially interested in the potential
reactivity of exo-cyclic vinylsilanes and in particular in 2-
methylidene-1-silacyclohexanes. To our surprise, in spite
of the importance of vinylsilanes in organic synthesis [2],
only a handful of examples of such organosilicon com-
pounds are described in the literature. Most commonly,
previously reported 2-methylidenesilacycloalkanes have a
second heteroatom within the ring and sometimes have
substituents on the olefinic carbon. Such compounds can
be prepared from tethered alkynes by intramolecular silyl-
formylation [3–5], hydrosilylation [6] or bis-silylation [7,8].
Other reactions such as radical cyclization [9], nickel-cata-
lyzed photolysis of unsaturated organosilanes [10] or ruthe-
nium-catalyzed silylation of ethylene [11], only lead to the
formation of methylidenesilacycloalkanes derivatives as
minor products.
*
Corresponding author. Tel.: +33 1 69 15 72 95; fax: +33 1 69 15 62 78.
E-mail address: lublanco@icmo.u-psud.fr (L. Blanco).
Present address: Institute of Chemical Research of Catalonia (ICIQ),
1
Av. Pa¨ısos Catalans, 16, 43007 Tarragona, Spain.
0022-328X/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.08.061

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S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
R1 R2
Si
dibromohex-1-ene 4 and 5 with the same ratio 85:15 was
isolated by distillation and used in the next steps without
separation of the isomers. No separation of the isomeric
compounds 2 and 3 or 4 and 5 could be observed by liquid
chromatography over silica gel. The overall yield of this
two steps substitution (95%) was higher than the reported
yield of the substitution using PBr3 (56%) [23].
7
2.1. Reactions in the Barbier-type conditions
Br
R1
X
R2
X
+
Si
Br
In a first approach we used the conditions reported for
the preparation of a 2-methylidene-1-silacyclobutane [21].
Addition of a 0.85:0.15:1 mixture of 2,6-dibromohexene
4, 1,6-dibromohexene 5 and trichloromethylsilane 6a
(R1 = Me, R2 = X = Cl) to an excess of magnesium (acti-
vated by reaction with 1,2-dibromoethane) in THF gave
an exothermic reaction and after heating to reflux during
1 h, the chlorosilane 7a was isolated in 9% yield by distilla-
tion (Scheme 3). A better yield (28%) was obtained after
addition over 30 min of the same mixture of compounds
4, 5 and 6a to a stoichiometric amount of activated magne-
sium and subsequent heating of the reaction mixture at
60 °C for 2 h. Apart from the ratio (4 + 5):6a, all the others
conditions tested (lower concentration of reactants,
increased or decreased addition time, lower or higher tem-
perature of the additional heating, activation of magne-
sium with zinc chloride, replacement of THF by DME,
reaction in refluxing toluene in the presence of sodium)
gave lower yields. A slightly better yield (31%) has been
obtained using a ratio (4 + 5):6a = 1:2 but the purification
of the chlorosilane 7a was complicated by the presence of a
larger amount of silanic oligomers. In order to obtain an
easily workable crude product we preferred to run the reac-
tion with the ratio (4 + 5):6 = 1:1.
4
Scheme 1.
2. Results and discussion
2,6-Dibromohex-1-ene 4 was prepared from hex-5-en-1-
ol 1 using a reported method [23] (Scheme 2). Addition of
bromine to the alcohol 1 and treatment with potassium
hydroxide of the resulting dibromide in ether gave a
85:15 mixture of 5-bromohex-5-en-1-ol 2 and the previ-
ously unnoticed 6-brominated isomer 3. Various attempts
with other bases have been made in order to increase the
proportion of the desired isomer 2 but lower selectivities
were obtained (with sodium hydroxide powder without sol-
vent at 40–50 °C, 2:3 was 65:35; with a solution of tetrabu-
tylammonium hydroxide in methanol at room temperature,
2:3 was 35:65; with an aqueous solution of lithium hydrox-
ide in ether at reflux, 2:3 was 73:27). Substitution of the
hydroxy group of the compounds 2 and 3 by a bromine
atom was achieved by treatment of the corresponding
methylsulfonates with LiBr in N-methylpyrrolidinone
(NMP) at room temperature. A mixture of 2,6- and 1,6-
With the optimum conditions of the Barbier-type reac-
tion described above various dihalo- and trichlorosilanes
6 [24] were used to prepare 2-methylidenesilacyclohexanes
7a–g. Such as for the product 7a, the chlorosilane 7b and
the hydrogenosilane 7f were isolated by distillation.
OH
1
1) Br2, Et2O, rt
2) KOH, reflux
85%
Br
R1
X
R2
X
Br
+
Si
+
5
Br
Br
+
OH
OH
6
4
2
3
85 .............................. 15
Mg*, THF
1) MeSO2Cl, NEt3, DCM, rt
2) LiBr, NMP, rt
95%
Br
R1 R2
Si
Br
Br
+
Br
5
4
7
85 .............................. 15
Scheme 3. Preparation of 2-methylidenesilacyclohexanes 7 in the Barbier-
Scheme 2. Preparation of dibromohexenes 4 and 5.
type conditions.

S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
5533
All the others methylidenesilacyclohexanes have been puri-
2.2. Reactions with a Grignard reagent
fied by silica gel column chromatography. The results are
reported Table 1.
Reactions in THF of various dihalosilanes and trihalo-
silanes 6 [24] with 1 equiv of organodimagnesium reagent
prepared from the mixture of dibromohexenes 4 and 5
(4:5 = 85:15), between 20 and 30 °C or at 10 °C, followed
by heating to reflux have generally allowed the preparation
of 2-methylidene-1-silacyclohexanes 7 (Scheme 4). In these
conditions, a 1-silacyclohept-2-ene was also never detected.
Yields were calculated from the number of moles of orga-
nometallic reagents used in each reaction with the assump-
tion that the ratio of the reagent derived from the
dibromide 4 to that derived from the isomer 5 was also
85:15 (see Table 1).
When the preparation of the organodimetallic reagent
was made between 20 and 30 °C, the yields of the methylid-
enesilacyclohexanes 7b–e and 7g–i were in the range 28–
60%. The allylmethylsilacyclohexane 7d was obtained in
6% yield starting from the dichlorosilane 6d but the yield
was increased to 24% using the corresponding difluorosi-
lane 6d0. However such improvement was not general: for
the preparation of the 3-chloropropylsilane 7g and the
3-bromopropylsilane 7h, the yields starting with dichloro-
silanes were higher than those obtained with the corre-
sponding difluorosilanes. Using these conditions it was
also possible to obtained chlorosilacyclohexanic com-
pounds using trichlorosilanes but the yields were very
low: the phenylated product 7b was isolated in 7% yield
and traces of the methylated product 7a were observed.
With the dichloromethylsilanes 6c, 6d, 6e, 6f and 6g
bearing phenyl, allyl, vinyl, hydrogen or 3-chloropropyl
substituent and with the trichorophenylsilane 6b the yields
were in the range 4–28%. The yield of the allylsilacyclohex-
ane 7d was higher from the difluorosilane 6d0 (27%) than
from the corresponding dichlorosilane 6d (22%). This trend
was not general and the vinylsilacyclohexane 7e was iso-
lated in a slightly better yield from the dichlorosilane 6e
(5%) than from the difluorosilane 6e0 (2%). However, the
high volatility of the latter could decrease the actual
amount of the silane involved in the reaction. The low yield
of the methylmethylidenesilacyclohexane 7f can be
explained in part by the difficulties to separate this com-
pound (bp = 51 °C) from THF (bp = 66 °C). This silane
is too instable to be purified by liquid chromatography
over silica gel. The reaction with the chloropropylsilane
6g gave the 3-chloropropylsilacyclohexane 7g (20%) and
the 1-methyl-2-methylidene-1-propyl-1-silacyclohexane 8
(9%) which should be formed by hydrolysis of the organo-
magnesium derivative of the chloropropylsilacyclohexane
7g. Such a side-reaction was avoided using a preformed
Grignard reagent (vide infra). We never observed, on the
spectra of the crude reaction products, the presence of sig-
nals of a 1-silacyclohept-2-ene which could be issued from
the 1,6-dibromohexene 5 although this dibromide was
totally transformed under the reaction conditions.
Table 1
Preparation of 2-methylidene-1-silacyclohexanes 7 from polyhalosilanes 6 and 2,6-dibromohex-1-ene 4
Polyhalosilanes
2-Methylidenesilacyclohexanes
Yield (%)
X
R1
R2
Barbier’s conditions
Grignard’s conditions
20–30 °Ca
10 °Ca
6a
6b
6c
6d
6d0
6e
6e0
6f
Cl
Cl
Cl
Cl
F
Cl
F
Cl
Cl
F
Me
Ph
Cl
Cl
Ph
Allyl
Allyl
Vinyl
Vinyl
H
3-Chloropropyl
3-Chloropropyl
3-Bromopropyl
3-Bromopropyl
3-Chloropropyl
7a
7b
7c
7d
7d
7e
7e
7f
28
28
18
22
27
4
2
5
20c
Traces
39
53
67
<13b
<21b
<17b
7
32
6
24
28
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Ph
0
55
28
60
35
33
0
6g
6g0
6h
6h0
6i
7g
7g
7h
7h
7i
51
40
35
42
36
Cl
F
Cl
a
Temperature of preparation of the organodimetallic reagent.
Me
Pr
Si
8
b
c
Impure product has been isolated (see text).
Compound 8 was also formed.

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S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
Br
124.5 2.5
149.5 1.7
Br
+
Br
Br
R1 R2
Si
5
4
14.7 3.2
85 .............................. 15
Mg*, THF
24.0 0.6
39.2 0.8
BrMg
30.6 0.3
MgBr
Fig. 1. 13C Chemical shifts for 2-methylidenesilacyclohexanes 7.
R1
X
R2
X
Si
then reflux, 1.25 h
been tested, in order to increase the yields of these reac-
tions, without success. Reaction at ꢀ5 °C, followed by
warming at 20 °C, of the dichlorosilane 6c with the 2,6-
dilithiated hex-1-ene prepared from lithium [25] and the
mixture of dibromohexenes 4 and 5 (4:5 = 85:15) gave also
the expected methylphenylsilacyclohexane 7c but the yield
(19%) has been lower than those obtained with the Grig-
nard derivative.
6
R1 R2
Si
7
Scheme 4. Preparation of 2-methylidenesilacyclohexanes 7 via a Grignard
reagent.
2.3. Comments
Comparison of the yields of the methylidenesilacyclo-
hexanes 7 obtained with the preformed organodimetallic
reagent or using the Barbier-type conditions shows that
the latter conditions appear more interesting only for the
synthesis of the compounds 7d and 7f bearing an allyl
group or an hydrogen atom on the silicon atom. It should
be underlined that the organodimetallic reagent was gener-
ally prepared in about 50% yield. Comparison of the yields
of the silacyclohexanes 7 prepared using the Barbier type
conditions with the overall yields of the syntheses using
the Grignard conditions calculated from the utilized
amounts of dibromide 4 shows that the latter conditions
are generally more interesting, once again.
When the preparation of the organodimetallic reagent
was run at 10 °C the yields of the methylidenesilacyclohex-
anes 7a–e and 7g–i were between 13% and 66%. By com-
parison to the reactions made with the organodimetallic
reagent prepared between 20 and 30 °C, the general trend
was an increase of the yields. The greatest improvements
were observed for the preparation of the chlorosilanes 7a
(from traces to 39% yield) and 7b (from 7% to 53% yield),
however a decrease of the yield was noticed in some cases.
Moreover after the synthesis of the allylated and the viny-
lated silacyclohexanes 7d and 7e with the organometallic
reagent prepared at 10 °C, the purifications by silica gel
chromatography were more tedious and only impure com-
pounds were isolated (for the other cases and with the
organometallic reagent prepared at 20–30 °C, the purities
of the isolated products were higher than 95%). With this
Grignard reagent, the methylidenesilane 7f could not be
prepared from dichloromethylsilane 6f, regardless of the
reaction temperature.
Another factor that partially explains the modest yields
of the syntheses of 2-methylenesilacyclohexanes 7 is their
instability in the reaction medium. For example, 82% of
the methylidenesilacyclohexane 7c was degradated after
heating in THF at 68–70 °C for 16 h in the presence of
equimolecular amounts of MgBr2 and MgCl2.
1
The H NMR spectra of the 2-methylidenesilacyclohex-
The stability of the organometallic reagent, prepared
from 4 + 5 seems to decrease when raising the temperature.
When this reagent was heated for 2 h at 50 °C before addi-
tion of the dichlorosilane 6c and the subsequent heating, no
signals corresponding to the silacyclohexane 7c were
observed in 1H NMR spectrum of the crude product.
Unfortunately, we did not succeed to prepare this reagent
at 0 °C with the usual magnesium turnings. We postulate
that the reagent formed from the dibromohexene 4 is an
organodimetallic species, however, the formation of a 2-
methylidene-1-magnesiacyclohexane cannot be ruled out.
Other modifications of the reaction conditions (decrease
of the concentration of reactants, addition of CuCN) have
anes 7 show two signals (one between 5.66 and 5.40 ppm,
the other between 5.34 and 5.06 ppm) attributed to the
methylenic protons. Their 13C NMR spectra show that
the chemical shifts of the carbon atoms of the core are
slightly variable (Fig. 1).
3. Conclusion
Two related synthetic methods have been optimized to
prepare 2-methylidenesilacyclohexanes 7 from magnesium,
di- or trihalosilanes and 2,6-dibromohex-1-ene via a pre-
formed organodimetallic reagent or using Barbier-type
conditions. No general trend was observed regarding the

S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
5535
nature of the halogen (chlorine or fluorine) on the starting
silane. Lowering the temperature of the Grignard reagent
formation resulted in general improvement of the isolated
yields. We should emphasized the simplicity of theses meth-
ods where two carbon-silicon bonds were formed in the
same flask and the instability of the intermediate reagent
and/or of the products in the reaction medium. In many
cases, the yields were good enough to allow the use of these
2-methylidenesilacyclohexanes as synthetic intermediates.
The chlorosilanes 7a and 7b are particularly interesting,
they are useful synthons to prepare various methylidenesi-
lacyclohexanes by nucleophilic substitution of the chlorine
atom. Studies on the reactivity and the synthetic utility of
this scarcely known family of vinylsilanes are ongoing in
our laboratory and results will be published in due course.
79.7 mmol) in tetraglyme (14 mL), as described by Farooq
and Tiers [26] (oil bath temperature = 70 °C), gave the
difluorosilane 6d0, isolated as a colorless oil (3.63 g, 87%)
after purification by distillation under argon atmosphere:
bp = 63 °C/760 Torr; 13C NMR (62.9 MHz, CDCl3) d
ꢀ5.1 (t, JC–F = 16 Hz, Si–CH3), 20.6 (t, JC–F = 16 Hz, Si–
CH2), 116.9 (@CH2), 129.2 (@CH); IR 3087 (m@CH),
2980, 1636 (mC@C), 1419 (d@CH), 1271 (dSi–CH ), 1180, 911
3
(d@CH), 879, 812.
4.2.2. Difluoromethylvinylsilane (6e0)
Reaction of dichloromethylvinylsilane 6e (5 mL,
38 mmol) and sodium tetrafluoroborate (13.84 g,
126.1 mmol) in tetraglyme (16 mL), as described by Farooq
and Tiers [26] (oil bath temperature = 130 °C), gave the
difluorosilane 6e0, isolated as a colorless oil (1.24 g, 30%)
after purification by distillation under argon atmosphere:
4. Experimental
1
bp = 28 °C/760 Torr; H NMR (400 MHz, CDCl3) d 0.44
4.1. General informations
(t, JH–F = 6.1 Hz, 3H, Si–CH3), 6.00–6.11 (m, 1H, Si–
CH), 6.21–6.34 (m, 2H, CH2); 13C NMR (62.9 MHz,
CDCl3) d ꢀ5.1 (t, JC–F = 17 Hz, Si–CH3), 129.1 (CH2),
138.9 (t, JC–F = 14 Hz, Si–CH); IR 2961, 2931, 2874,
All reactions were performed under an argon atmo-
sphere using oven-dried glassware. All the commercially
available silanes 6a–f were used without further purifica-
tion. Sodium tetrafluoroborate and hexachloroplatinic acid
were kept in a desiccator filled with P2O5. THF was dis-
tilled prior to use over the radical anion of benzophenone.
Cyclohexane was filtered through basic alumina prior to
use. Column chromatographies were performed on silica
gel SDS (70–200 lm).
NMR spectra were recorded on Bruker AC 200, AC 250
or DRX 400 spectrometers at room temperature. Chemical
shifts (d) are reported in ppm with respect to tetramethylsi-
lane, a signal of the solvent (CDCl3) was used as internal
reference (CHCl3: 7.27 and CDCl3: 77.0 ppm). The assign-
ment of certain signals was done after COSY, HSQC,
HMBC, DEPT or TOCSY experiments on the DRX 400
instrument. IR spectra were recorded on a Perkin–Elmer
FT-IR Spectrum One instrument with neat samples, the
band positions are given in cmꢀ1. Mass spectra were
obtained by electron ionization method (70 eV) on a Ner-
mag R10-10 instrument, coupled to an OKI DP125 chro-
matographer (Low Resolution) or on a Finnigan MAT 95
S instrument (High Resolution). Elemental analyses were
made by the Microanalyse Service of the Institut de Chimie
des Substances Naturelles at Gif-sur-Yvette (ICSN).
2861, 1464, 1271 (dSi–CH ), 1123, 1073, 798.
3
4.2.3. (3-Chloropropyl)difluoromethylsilane (6g0)
Reaction of (3-chloropropyl)dichloromethylsilane 6g
(2.73 g, 14.3 mmol) and sodium tetrafluoroborate (5.40 g,
49.2 mmol) in tetraglyme (6 mL) as described by Farooq
and Tiers [26] (reaction temperature = 120 °C), gave the
difluorosilane 6g0, isolated as a colorless oil (1.85 g, 82%)
after purification by distillation under reduced pressure:
bp = 70 °C/5 Torr; 1H NMR (250 MHz, CDCl3) d 0.40
(t, JH–F = 6.3 Hz, 3H, Si–CH3), 0.87–1.06 (m, 2H, Si–
CH2), 1.83–2.03 (m, 2H, Si–CH2–CH2), 3.57 (t,
J = 6.5 Hz, 2H, CH2–Cl); 13C NMR (62.9 MHz, CDCl3)
d ꢀ4.7 (t, JC–F = 16 Hz, Si–CH3), 10.8 (t, JC–F = 16 Hz,
Si–CH2), 24.8 (Si–CH2–CH2), 46.6 (CH2–Cl); LR–MS m/
z 145 (2, M+ ꢀ 15), 143 (8, M+ ꢀ 15), 131 (13), 119 (6),
107 (7), 82 (6), 81 (100), 80 (5), 69 (20), 47 (10), 43 (3);
IR 2962, 2894, 1439, 1315, 1270 (dSi–CH ), 1167, 1123,
3
997, 879, 807; HR–MS calculated for C4H9ClF2Si
158.0130, found 158.0131 (M+).
4.2.4. (3-Bromopropyl)dichloromethylsilane (6h) [27]
To cyclohexane (30 mL) with Speier’s catalyst (ꢁ1 mg)
was added at room temperature a mixture of dichloro-
methylsilane (4.7 mL, 45 mmol) and allyl bromide
(5 mL, 57.4 mmol) and the reaction mixture was stirred
and heated at reflux overnight. After evaporation of the
solvent, distillation of the residue under reduced pressure
gave 6h as a colorless oil (1.6 g, 15%): bp = 82 °C/8 Torr;
13C NMR (50.3 MHz, CDCl3) d 5.2 (Si–CH3), 20.5 (Si–
CH2), 26.0 (Si–CH2–CH2), 35.3 (CH2–Br); LR–MS m/z
225 (2, M+ ꢀ 15), 223 (13, M+ ꢀ 15), 221 (28,
M+ ꢀ 15), 219 (16, M+ ꢀ 15), 179 (28), 177 (17), 159
(8), 157 (6), 117 (13), 115 (82), 114 (8), 113 (100), 65
(5), 63 (15), 43 (82).
4.2. Preparation of dihalosilanes
Allyldifluororomethylsilane 6d0 [26], (3-bromopro-
pyl)dichloromethylsilane 6h [27] and dichloro(3-chloropro-
pyl)phenylsilane 6i [28] are known products and only
complementary spectroscopic data to the literature are
provided.
4.2.1. Allyldifluoromethylsilane (6d0)
Reaction of allyldichloromethylsilane 6d (5 mL,
34.2 mmol) and sodium tetrafluoroborate (8.75 g,

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S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
4.2.5. (3-Bromopropyl)difluoromethylsilane (6h0)
organic phases were concentrated under reduced pressure
and the chloromethylidenesilacyclohexane was isolated by
distillation. When the resulting product was not a chloro-
silane, a saturated NH4Cl aqueous solution and diethyl
ether were added. After separation, the aqueous phase
was extracted two times with diethyl ether. The combined
organic phases were washed with water, dried over
Na2SO4, concentrated under reduced pressure and the
methylidenesilacyclohexane was purified by silica gel col-
umn chromatography or distillation.
Reaction of dichlorosilane 6h (0.94 g, 3.98 mmol) and
sodium tetrafluoroborate (0.895 g, 8.15 mmol) in tetrag-
lyme (1 mL), as described by Farooq and Tiers [26] (reac-
tion temperature = 120 °C), gave the difluorosilane 6h0,
isolated as a colorless oil (0.65 g, 80%) after purification
by distillation under reduced pressure: bp = 90 °C/6 Torr;
1H NMR (250 MHz, CDCl3) d 0.40 (t, JH–F = 6.3 Hz,
3H, Si–CH3), 0.88–1.09 (m, 2H, Si–CH2), 1.90–2.02 (m,
2H, Si–CH2–CH2), 3.42 (t, J = 6.6 Hz, 2H, CH2–Br); 13C
NMR (62.9 MHz, CDCl3) d ꢀ4.2 (t, JC–F = 16 Hz, Si–
CH3), 12.6 (t, JC–F = 16 Hz, Si–CH2), 25.0 (Si–CH2–
CH2), 35.6 (CH2–Br); LR–MS m/z 189 (13, M+ ꢀ 15),
187 (13, M+ ꢀ 15), 147 (6), 145 (6), 143 (5), 123 (42), 109
(15), 107 (17), 83 (7), 82 (12), 81 (100), 80 (8), 69 (6), 47
4.3.2. General procedure B to synthesize 2-methylidene-1-
silacyclohexanes via a Grignard reagent
To a mixture of magnesium turnings (0.60 g, 24.7 mmol)
activated by 1,2-dibromoethane (70 lL, 0.81 mmol) in
THF (0.5 mL) was added over 1 h a solution of a 85:15
mixture of dibromohexenes 4 and 5 (2.42 g, 10 mmol)
and 1,2-dibromoethane (0.3 mL, 3.48 mmol) in THF
(20 mL). During the addition, temperature is maintained
under 30 °C then the reaction mixture was stirred 3 h at
20 °C and the resulting solution of Grignard reagent was
titrated. Generally a closed to 0.54 N solution was
obtained. On the assumption that organodimetallic com-
pounds are the sole products, the concentration of the pre-
pared Grignard reagents should be closed to 0.27 M. The
requisite volume of this Grignard reagent solution (1 equiv)
was added to a solution of a polyhalosilane in THF (the
volume of THF was calculated in order to obtain a
0.1 M solution of the reactants). The mixture was heated
to reflux for 1.4 h. Further treatment of the mixture was
made as previously described for the Barbier type
conditions.
(9), 43 (81); IR 2965, 2855, 1436, 1270 (dSi–CH ), 1242,
3
1035, 874, 802; HR–MS calculated for C4H9BrF2Si
201.9625, found 201.9623 (M+).
4.2.6. Dichloro(3-chloropropyl)phenylsilane (6i)
After reaction of dichlorophenylsilane (5 mL,
34.2 mmol), allyl chloride (3.7 mL, 44.5 mmol) and Speier’s
catalyst as described by Speier et al. [28], distillation under
reduced pressure afforded a mixture of trichlorophenylsilane
and dichlorophenylpropylsilane (3.80 g, bp = 84–92 °C/
6 Torr) and the dichloro(3-chloropropyl)phenylsilane 6i as
a colorless oil (2.48 g, 29%): bp = 82 °C/0.1 Torr; 1H
NMR (200 MHz, CDCl3) d 1.43–1.58 (m, 2H, Si–CH2),
1.91–2.15 (m, 2H, Si–CH2–CH2), 3.60 (t, J = 6.6 Hz, 2H,
CH2–Cl), 7.40–7.59 (m, 3H, HAr), 7.68–7.82 (m, 2H, HAr);
13C NMR (50.3 MHz, CDCl3) d 12.2 (Si–CH2), 25.9 (Si–
CH2–CH2), 46.5 (CH2–Cl), 128.4 (CHAr), 131.5 (CHAr),
131.8 (CHAr), 133.4 (CAr); LR–MS m/z 256 (2, M+), 254
(4, M+), 252 (5, M+), 214 (11), 212 (32), 210 (31), 179 (12),
177 (68), 176 (12), 175 (100), 174 (33), 78 (14), 77 (16); IR
3031 (m@CH), 2957, 1591 (mC@C), 1431 (mSi–Ar), 1312 (d@C–H),
1268, 1162 (dSi–Ar), 1118, 997, 909, 740 (d@CH), 696; HR–
MS calculated for C9H11Cl3Si 251.9700, found 251.9710
(M+).
4.3.3. General procedure B0 to synthesize 2-methylidene-1-
silacyclohexanes via a Grignard reagent
Same conditions than in procedure B apart from the
temperature of the reaction during the addition of the mix-
ture dibromohexenes 4 and 5 to the activated magnesium.
This time, the reaction temperature was maintained to
10 °C.
4.3. Preparation of 2-methylidene-1-silacyclohexanes
4.3.4. 1-Chloro-1-methyl-2-methylidene-1-silacyclohexane
(7a)
4.3.1. General procedure A to synthesize 2-methylidene-1-
silacyclohexanes under Barbier type conditions
The compound 7a was prepared from trichloromethylsi-
lane 6a and isolated, as a colorless oil, by distillation under
reduced pressure. (a) From trichlorosilane 6a (1.2 mL,
10 mmol) and using procedure A was isolated 7a (0.42 g,
28%). (b) From trichlorosilane 6a (0.14 mL, 1.17 mmol)
and using procedure B0 was isolated 7a (65 mg, 39%).
Bp = 52 °C/5 Torr; 1H NMR (200 MHz, CDCl3) d 0.54
(s, 3H, CH3), 0.80 (ddd, J = 5.4, 9.9, 15.5 Hz, 1H, H6),
1.00–1.17 (m ,1H, H60), 1.23–1.44 (m, 1H, H4), 1.63–2.01
(m, 3H, H40 + H5 + H50), 2.28–2.57 (m, 2H, H3 + H30),
5.34 (broad s, 1H, C2@CH2), 5.58 (broad s, 1H,
C2@CH2); 13C NMR (62.9 MHz, CDCl3) d ꢀ1.2 (CH3),
17.8 (C6), 23.5 (C5), 30.3 (C4), 38.4 (C3), 124.1
(C2@CH2), 148.9 (C2); LR–MS m/z 162 (22, M+), 160
To a mixture of magnesium turnings (0.535 g, 22 mmol)
activated by 1,2-dibromoethane (0.17 mL, 2 mmol) in THF
(5 mL) was added slowly (exothermic reaction) a solution
of a polyhalosilane (10 mmol) and a 85:15 mixture of di-
bromohexenes 4 and 5 (2.42 g, 10 mmol) in THF (5 mL).
Then, the reaction mixture was stirred at 60 °C for 2 h.
When the resulting product was a chlorosilane, the reaction
mixture was concentrated under reduced pressure and dry
pentane was added. The organic phase was separated by fil-
tration through a filtrating canula equipped with paper and
recovered under argon. The solid part was washed four
times with dry pentane, the organic phase being removed
each time through the filtrating canula. The combined

S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
5537
(61, M+), 145 (16), 132 (45), 119 (57), 117 (67), 96 (52), 93
(26), 92 (34), 81 (100), 80 (61), 79 (97), 78 (52), 67 (69), 66
(40), 65 (59), 63 (98), 53 (24), 43 (27); IR 3075 (m@CH), 3039
(50), 122 (13), 121 (100), 119 (15), 109 (23), 105 (54), 96
(11), 80 (15), 53 (10), 43 (18); IR 3068 (m@CH), 3045 (m@CH),
2916, 2852, 1618 (mC@C), 1428 (mSi–Ar), 1250 (dSi–CH ), 1111
3
(m@CH), 2922, 2856, 1642 (mC@C), 1439, 1260 (dSi–CH ), 925,
(dSi–Ar), 1000, 923, 795 (d@CH), 728; HR–MS calculated
3
894 (d@CH), 802; HR–MS calculated for C7H1335ClSi,
for C13H18Si 202.1178, found 202.1177 (M+).
160.0470, found 160.0461 (M+).
4.3.7. 1-Allyl-1-methyl-2-methylidene-1-silacyclohexane
(7d)
4.3.5. 1-Chloro-2-methylidene-1-phenyl-1-silacyclohexane
(7b)
The compound 7d was prepared from allyldichloro-
methylsilane 6b or the corresponding difluorosilane 6d0
and isolated, as a colorless oil, after chromatography (pen-
tane). (a) From dichlorosilane 6d (2.6 mL, 10 mmol) and
using procedure A was isolated 7d (0.31 g, 22%). (b) From
dichlorosilane 6d (0.65 mL, 2.52 mmol) and using proce-
dure B was isolated 7d (21 mg, 6%). (c) From difluorosilane
6d0 (1.52 mL, 12.5 mmol) and using procedure A was iso-
lated 7d (0.47 g, 27%). (d) From difluorosilane 6d0
(0.27 mL, 2.22 mmol) and using procedure B was isolated
7d (75 mg, 24%). Rf (pentane) = 0.64; 1H NMR
(250 MHz, CDCl3) d 0.10 (s, 3H, CH3), 0.58 (ddd,
J = 4.9, 9.8, 14.6 Hz, 1H, H6), 0.80 (ddd, J = 4.9, 7.2,
14.6 Hz, 1H, H60), 1.33–1.51 (m, 1H, H4), 1.57–1.89 (m,
H40 + H5 + H50) and 1.67 (d, J = 7.0 Hz, CH2–CH@CH2)
(5 H), 2.28–2.41 (m, 2H, H3 + H30), 4.84 (d, J = 9.8 Hz,
1H, CH@CH2 cis), 4.88 (d, J = 18.4 Hz, 1H, CH@CH2
trans), 5.15 (d, J = 3.4 Hz, 1H, C2@CH2), 5.51 (d,
J = 3.4 Hz, 1H, C2@CH2), 5.80 (ddt, J = 9.8, 18.4, 7 Hz,
1H, CH@CH2); 13C NMR (62.9 MHz, CDCl3) d ꢀ5.9
(CH3), 13.1 (C6), 20.9 (Si–CH2Allyl), 24.3 (C5), 30.8 (C4),
39.8 (C3), 113.0 (CH@CH2), 122.0 (C2@CH2), 134.7
(CH@CH2), 151.2 (C2); LR–MS m/z 166 (6, M+), 151
(2), 126 (25), 125 (100), 124 (18), 123 (11), 109 (11), 99
(21), 98 (12), 97 (94), 95 (20), 85 (14), 83 (14), 71 (24), 69
(16), 67 (11), 59 (65), 55 (22), 53 (13), 45 (42), 43 (79), 41
(14), 39 (16); IR 3077 (m@CH), 3041 (m@CH), 2917, 2852,
1630 (mC@C), 1438, 1419 (d@CH ), 1251 (dSi–CH ), 1152, 990
The compound 7b was prepared from trichlorophenylsi-
lane 6b and isolated, as a colorless oil, by distillation under
reduced pressure. (a) From trichlorosilane 6b (1.6 mL,
10 mmol) and using procedure A was isolated 7b (0.49 g,
28%). (b) From trichlorosilane 6b (1.6 mL, 10 mmol) and
using procedure B was isolated 7b (0.12 g, 7%). (c) From
trichlorosilane 6b (0.195 mL, 1.22 mmol) and using proce-
dure B0 was isolated 7b (0.122 g, 53%). Bp = 70 °C/
1
0.08 Torr; H NMR (200 MHz, CDCl3) d 1.14–1.41 (m,
2H, H6 + H60), 1.46–1.64 (m, 1H, H4), 1.69–1.85 (m, 1H,
H40), 1.85–2.04 (m, 2H, H5 + H50), 2.39–2.69 (m, 2H,
H3 + H30), 5.30 (d, J = 2.9 Hz, 1H, C2@CH2), 5.65 (d,
J = 2.9 Hz, 1H, C2@CH2), 7.30–7.58 (m, 3H, m- and p-
HAr), 7.58–7.81 (m, 2H, o-HAr); 13C NMR (62.9 MHz,
CDCl3) d 17.0 (C6), 24.2 (C5), 30.7 (C4), 39.3 (C3), 127.0
(C2@CH2), 128.5 (m-CHAr), 131.1 (p-CHAr), 132.7 (CAr),
134.6 (o-CHAr), 147.7 (C2); LR–MS m/z 224 (14, M+),
222 (38, M+), 167 (10), 166 (10), 154 (12), 146 (12), 145
(11), 144 (36), 143 (21), 142 (16), 141 (49), 140 (29), 131
(29), 129 (13), 118 (13), 117 (10), 116 (34), 105 (11), 91
(25), 81 (14), 80 (23), 79 (18), 67 (10), 65 (44), 63 (100),
53 (16), 51 (12); IR 3071 (m@CH), 3051 (m@CH), 2924,
2856, 1590 (mC@C), 1429 (mSi–Ar), 1114 (dSi–Ar), 936, 891
(d@CH), 736, 672; HR–MS calculated for C12H1535ClSi,
222.0626, found 222.0625 (M+).
4.3.6. 1-Methyl-2-methylidene-1-phenyl-1-silacyclohexane
(7c)
2
3
(d@CH), 921, 894 (d@CH), 820; HR–MS calculated for
The compound 7c was prepared from dichloromethyl-
phenylsilane 6a and isolated, as a colorless oil, after chro-
matography (pentane). (a) From dichlorosilane 6c
(1.63 mL, 10 mmol) and using procedure A was isolated
7c (0.31 g, 18%). (b) From dichlorosilane 6c (0.33 mL,
2.01 mmol) and using procedure B was isolated 7c
(0.11 g, 32%). (c) From dichlorosilane 6c (0.44 mL,
2.7 mmol) and using procedure B0 was isolated 7c (0.31 g,
C10H18Si 166.1178, found 166.1178 (M+).
4.3.8. 1-Methyl-2-methylidene-1-vinyl-1-silacyclohexane
(7e)
The compound 7e was prepared from dichloromethylvi-
nylsilane 6e or the corresponding difluorosilane 6e0 and iso-
lated, as a colorless oil, after chromatography (pentane).
(a) From dichlorosilane 6e (2 mL, 15.3 mmol) and using
procedure A was isolated 7e (73.2 mg, 4%). (b) From
dichlorosilane 6e (2.26 mL, 2.22 mmol) and using proce-
dure B was isolated 7e (0.58 g, 28%). (c) From difluorosi-
lane 6e0 (0.96 g, 8.85 mmol) and using procedure A was
isolated 7e (18 mg, 2%). Rf (pentane) = 0.63; 1H NMR
(250 MHz, CDCl3) d 0.19 (s, 3H, CH3), 0.67 (ddd,
J = 5.1, 9.2, 14.4 Hz, 1H, H6), 0.87 (ddd, J = 5.1, 7.7,
14.4 Hz, 1H, H60), 1.36–1.50 (m, 1H, H4), 1.50–1.66 (m,
1H, H40), 1.66–1.83 (m, 2H, H5 + H50), 2.23–2.50 (m,
2H, H3 + H30), 5.16 (d, J = 3.6 Hz, 1H, C2@CH2), 5.51
(d, J = 3.6 Hz, 1H, C2@CH2), 5.77 (dd, J = 4.6, 19.6 Hz,
1H, CH@CH2 trans), 6.04 (dd, J = 4.6, 14.6 Hz, 1H,
1
66%). Rf (pentane) = 0.47; H NMR (250 MHz, CDCl3)
d 0.35 (s, 3H, CH3), 0.79 (ddd, J = 3.9, 10.5, 14.7 Hz,
1H, H6), 1.16 (ddd, J = 3.9, 7.8, 14.7 Hz, 1H, H60), 1.39–
1.55 (m, 1H, H4), 1.60–1.80 (m, 2H, H40 + H5), 1.80–
2.20 (m, 1H, H50), 2.22–2.58 (m, 2H, H3 + H30), 5.20 (d,
J = 3.4 Hz, 1H, C2@CH2), 5.60 (d, J = 3.4 Hz, 1H,
C2@CH2), 7.30–7.45 (m, 3H, m- and p-HAr), 7.48–7.59
(m, 2H, o-HAr); 13C NMR (62.9 MHz, CDCl3) d ꢀ4.4
(CH3), 13.6 (C6), 24.4 (C5), 30.9 (C4), 39.8 (C3), 123.4
(C2@CH2), 127.8 (m-CHAr), 129.0 (p-CHAr), 134.2 (o-
CHAr), 136.8 (CAr), 150.5 (C2); LR–MS m/z 202 (41,
M+), 187 (19), 159 (31), 145 (15), 134 (30), 131 (12), 124

5538
S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
CH@CH2 cis), 6.18 (dd, J = 14.6, 19.6 Hz, 1H, CH@CH2);
13C NMR (100 MHz, CDCl3) d ꢀ5.6 (CH3), 13.7 (C6), 24.4
(C5), 30.9 (C4), 39.8 (C3), 122.4 (C2@CH2), 133.1
(CH@CH2), 136.5 (CH@CH2), 150.9 (C2); LR–MS m/z
152 (1, M+), 137 (17), 124 (30), 123 (16), 111 (61), 110
(100), 109 (84), 97 (28), 96 (25), 95 (23), 84 (15), 83 (21),
80 (12), 79 (11), 71 (44), 70 (30), 69 (17), 67 (11), 59 (22),
58 (17), 57 (12), 55 (39), 54 (22), 53 (19), 45 (40), 44 (23),
43 (48); IR 3046 (m@CH), 2923, 2853, 1641 (mC@C), 1447,
(33), 109 (29), 99 (16), 98 (11), 97 (100), 96 (18), 93 (44),
92 (49), 81 (39), 80 (57), 79 (33), 62 (17), 59 (30), 43 (18);
IR 3040 (m@CH), 2916, 2852, 1606 (mC@C), 1437, 1252
(dSi–CH ), 1119, 1003, 921, 893 (d@CH ), 794. Anal. Calc.
for C10H19ClSi: C, 59.23; H, 9.44. Found: C, 59.22; H,
9.49%.
3
2
4.3.11. 1-(3-Bromopropyl)-1-methyl-2-methylidene-1-
silacyclohexane (7h)
1403 (dSi–CH ), 1008, 952, 922, 893 (d@CH), 866, 796 (d@CH),
The compound 7h was prepared from (bromopro-
pyl)dichloromethylsilane 6h or the corresponding difluo-
rosilane 6h0 and isolated, as a colorless oil, after
chromatography (pentane). (a) From dichlorosilane 6h
(0.64 g, 2.71 mmol) and using procedure B was isolated
7h (0.34 g, 60%). (b) From dichlorosilane 6h (0.30 g,
1.26 mmol) and using procedure B0 was isolated 7h
(90 mg, 35%). (c) From difluorosilane 6h0 (0.61 g, 3.01
mmol) and using procedure B was isolated 7h (0.225 g,
35%). (d) From difluorosilane 6h0 (0.27 g, 1.26 mmol) and
using procedure B0 was isolated 7h (0.11 g, 42%). Rf (pen-
3
749; HR–MS calculated for C9H16Si 152.1021, found
152.1016 (M+).
4.3.9. 1-Methyl-2-methylidene-1-silacyclohexane (7f)
From dichlorosilane 6f (1.55 mL, 15 mmol) and using
procedure A was isolated, after purification by distillation
under argon atmosphere, the compound 7f as a colorless
oil (77.5 mg, 5%). Bp = 51 °C/760 Torr; 1H NMR
(250 MHz, CDCl3) d 0.22 (d, J = 3.6 Hz, 3H, CH3), 0.60
(ddd, J = 4.9, 10.0, 19.4 Hz, 1H, H6), 0.86–1.02 (m, 1H,
H60), 1.30–1.51 (m, 1H, H4), 1.51–1.75 (m, 3H,
H40 + H5 + H50), 2.23–2.49 (m, 2H, H3 + H30), 3.99–
4.09 (m, 1H, H1), 5.21 (d, J = 3.4 Hz, 1H, C2@CH2),
5.52 (d, J = 3.4 Hz, 1H, C2@CH2); 13C NMR (62.9 MHz,
CDCl3) d ꢀ6.9 (CH3), 12.6 (C6), 24.6 (C5), 30.8 (C4),
40.0 (C3), 122.4 (C2@CH2), 150.0 (C2) [29].
1
tane) = 0.47; H NMR (400 MHz, CDCl3) d 0.13 (s, 3H,
CH3), 0.62 (ddd, J = 4.5, 10.1, 14.5 Hz, 1H, H6), 0.73–
0.82 (m, CH2–CH2–CH2Br) and 0.77 (ddd, J = 4.5, 7.4,
14.5 Hz, H60) (3 H), 1.37–1.50 (m, 1H, H4), 1.55–1.61
(m, 1H, H40), 1.61–1.77 (m, 1H, H5), 1.78–1.88 (m, H50)
and 1.78 (quintuplet, J = 7 Hz, CH2–CH2Br) (3 H), 2.26–
2.43 (m, 2H, H3 + H30), 3.42 (t, J = 7 Hz, 2H, CH2Br),
5.13 (d, J = 3.7 Hz, 1H, C2@CH2), 5.50 (d, J = 3.7 Hz,
1H, C2@CH2); 13C NMR (62.9 MHz, CDCl3) d ꢀ5.6
(CH3), 12.0 (CH2–CH2–CH2Br), 13.4 (C6), 24.4 (C5),
27.8 (CH2–CH2Br), 30.8 (C4), 36.9 (CH2Br), 39.7 (C3),
122.0 (C2@CH2), 151.1 (C2); LR–MS m/z 233 (2,
M+ ꢀ 15), 231 (2, M+ ꢀ 15), 204 (31), 191 (25), 189 (25),
167 (46), 165 (48), 164 (14), 163 (27), 161 (17), 139 (21),
138 (44), 137 (23), 136 (45), 125 (84), 123 (26), 109 (35),
97 (100), 96 (25), 81 (35), 80 (61), 71 (16), 59 (27), 43
(21); IR 3040 (m@CH), 2915, 2851, 1641 (mC@C), 1436, 1251
(dSi–CH ), 1231, 921, 893 (d@CH ), 793. Anal. Calc. for
4.3.10. 1-(3-Chloropropyl)-1-methyl-2-methylidene-1-
silacyclohexane (7g)
The compound 7g was prepared from dichloro(chloro-
propyl)methylsilane 6g or the corresponding difluorosilane
6g0 and isolated, as a colorless oil, after chromatography
(pentane). (a) From dichlorosilane 6g (1.08 g, 5,6 mmol)
and using procedure A were isolated 1-methyl-2-methyli-
dene-1-propyl-1-silacyclohexane
8
(79 mg) and 7g
(194 mg, 20%). (b) From dichlorosilane 6g (0.59 g,
3.08 mmol) and using procedure B was isolated 7g
(0.28 g, 55%). (c) From dichlorosilane 6g (0.23 g, 1.2 mmol)
and using procedure B0 was isolated 7g (0.10 g, 51%). (d)
From difluorosilane 6g0 (0.55 g, 3.47 mmol) and using pro-
cedure B was isolated 7g (0.17 g, 28%). (e) From difluoro-
silane 6g0 (0.19 g, 1.17 mmol) and using the general
procedure B0 was isolated 7g (82 mg, 40%). Rf (pen-
3
2
C10H19BrSi: C, 48.58; H, 7.75. Found: C, 48.77; H,
7.85%.
4.3.12. 1-(3-Chloropropyl)-2-methylidene-1-phenyl-1-
silacyclohexane (7i)
1
tane) = 0.45; H NMR (200 MHz, CDCl3) d 0.14 (s, 3H,
The compound 7i was prepared from dichloro(chloro-
propyl)phenylsilane 6i and isolated, as a colorless oil, after
chromatography (pentane). (a) From dichlorosilane 6i
(2.27 g, 8.96 mmol) and using procedure B was isolated 7i
(0.67 g, 33%). (b) From dichlorosilane 6i (198 mg,
0.78 mmol) and using procedure B0 was isolated 7i
CH3), 0.60 (ddd, J = 4.8, 9.8, 14.5 Hz, 1H, H6), 0.69–
0.85 (m, CH2–CH2–CH2Cl) and 0.70–0.83 (m, H60) (3H),
1.38–1.53 (m, 1H, H4), 1.53–1.77 (m, 2H, H40 + H5),
1.76–1.89 (m, CH2–CH2Cl) and 1.77–1.92 (m, H50) (3 H),
2.27–2.45 (m, 2H, H3 + H30), 3.53 (t, J = 6.9 Hz, 2H,
CH2Cl), 5.13 (d, J = 2.9 Hz, 1H, C2@CH2), 5.50 (d,
J = 2.9 Hz, 1H, C2@CH2); 13C NMR (62.9 MHz, CDCl3)
d ꢀ5.6 (CH3), 10.5 (CH2–CH2–CH2Cl), 13.4 (C6), 24.4
(C5), 27.5 (CH2–CH2Cl), 30.8 (C4), 39.8 (C3), 47.9
(CH2Cl), 121.9 (C2@CH2), 151.1 (C2); LR–MS m/z 189
(1, M+ ꢀ 15), 187 (2, M+ ꢀ 15), 162 (14), 161 (15), 160
(36), 159 (35), 147 (15), 145 (43), 134 (12), 132 (31), 126
(11), 125 (86), 123 (10), 123 (15), 121 (45), 120 (11), 119
1
(64 mg, 36%). Rf (pentane) = 0.32; H NMR (200 MHz,
CDCl3) d 0.78 (ddd, J = 4.2, 10.9, 14,.9 Hz, 1H, H6),
0.89–0.98 (m, 2H, CH2–CH2–CH2Cl), 1.10 (ddd, J = 4.2,
7.3, 14.9 Hz, 1H, H60), 1.42–1.57 (m, 1H, H4), 1.61–1.76
(m, 2H, H40 + H5), 1.76–1.93 (m, 3H, H50 + CH2–CH2Cl),
2.28–2.39 (m, 1H, H3), 2.39–2.50 (m, 1H, H30), 3.43 (t,
J = 7.0 Hz, 2H, CH2Cl), 5.19 (d, J = 4.0 Hz, 1H,
C2@CH2), 5.59 (d, J = 4.0 Hz, 1H, C2@CH2), 7.24–7.40

S. Dı´ez-Gonza´lez, L. Blanco / Journal of Organometallic Chemistry 691 (2006) 5531–5539
5539
(m, 3H, m- and p-HAr), 7.42–7.54 (m, 2H, o-HAr); 13C
NMR (62.9 MHz, CDCl3) d 10.0 (CH2–CH2–CH2Cl),
11.5 (C6), 24.2 (C5), 27.4 (CH2–CH2Cl), 30.7 (C4), 39.9
(C3), 47.9 (CH2Cl), 124.1(C2@CH2), 128.0 (m-CHAr),
129.3 (p-CHAr), 134.5 (o-CHAr), 135.1 (CAr), 148.9 (C2);
LR–MS m/z 264 (0,2, M+), 223 (11), 222 (20), 221 (20),
188 (17), 187 (100), 185 (13), 183 (40), 159 (67), 156 (13),
155 (10), 154 (38), 145 (21), 144 (23), 143 (16), 141 (41),
140 (12), 131 (15), 109 (26), 107 (26), 105 (38), 91 (23), 80
(19), 63 (16); IR 3068 (m@CH), 3046 (m@CH), 2917, 2853,
1590 (dC@C), 1428 (mSi–Ar), 1309, 1264, 1110 (dSi–Ar), 1013,
996 (d@CH), 924, 891 (d@CH), 735; HR–MS calculated for
C15H2135ClSi 264.1100, found 264.1096.
(b) Y. Uchimaru, H.J. Lautenschlager, A.J. Wynd, M. Tanaka, M.
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(b) M. Ishikawa, J. Ohshita, Y. Ito, Organometallics 5 (1986) 1518;
(c) J. Ohshita, Y. Isomura, M. Ishikawa, Organometallics 8 (1989)
2050.
[11] F. Delpech, J. Mansas, H. Leuser, S. Sabo-Etienne, B. Chaudret,
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Am. Chem. Soc. 117 (1995) 4419.
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Acknowledgement
(b) J. Robertson, D.S. Middleton, G. O’Connor, T. Sardharwala,
Tetrahedron Lett. 39 (1998) 669;
(c) J. Robertson, G. O’Connor, T. Sardharwala, D.S. Middleton,
Tetrahedron 56 (2000) 8309.
S.D.-G. thanks the Education, Research and Universi-
ties Department of the Basque Government (Spain) for a
doctoral fellowship.
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´
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