1-Phenyl-1-halo-1-silacyclohexanes

Article abstract of DOI:10.1134/S1070363216080132

The approaches to synthesis of 1-phenyl-1-halo-1-silacyclohexanes C₅H₁₀Si(Ph)X (X = F, Cl, Br) have been examined. 1-Phenyl-1-chloro-1-silacyclohexane has been prepared via the known reaction of phenyltrichlorosilane with dimagnesium

Full text of DOI:10.1134/S1070363216080132

ISSN 1070-3632, Russian Journal of General Chemistry, 2016, Vol. 86, No. 8, pp. 1854–1858. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © Е.N. Suslova, B.А. Shainyan, 2016, published in Zhurnal Obshchei Khimii, 2016, Vol. 86, No. 8, pp. 1316–1320.
1
-Phenyl-1-halo-1-silacyclohexanes
Е. N. Suslova and B. А. Shainyan*
Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
*
е-mail: bagrat@irioch.irk.ru
Received June 19, 2016
5
Abstract—The approaches to synthesis of 1-phenyl-1-halo-1-silacyclohexanes C H10Si(Ph)X (X = F, Cl, Br)
have been examined. 1-Phenyl-1-chloro-1-silacyclohexane has been prepared via the known reaction of
phenyltrichlorosilane with dimagnesium derivative of 1,5-dibromopentane; up to 20% of 1-bromo-1-phenyl-1-
silacyclohexane admixture is formed along with the target product. The minor product formation has been
prevented using an alternative method of chlorination of 1-phenyl-1-silacyclohexane with N-chloro-
succinimide. 1-Phenyl-1-fluoro-1-silacyclohexane has been obtained in close to quantitative yield via the
3
reaction of 1-phenyl-1-chloro-1-silacyclohexane with SbF and in 70% yield via its reaction with HF. The
synthesis of 1-phenyl-1-bromo-1-silacyclohexane via bromination of 1-phenyl-1-chloro-1-silacyclohexane with
N-bromosuccinimide has given the target product as a minor one, the major product being disiloxane formed
due to hydrolysis of the Si–Br bond.
Keywords: 1-phenyl-1-silacyclohexane, 1-halogeno-1-phenyl-1-silacyclohexane, halogenation, N-chloro(bromo)-
succinimide, antimony trifluoride, hydrofluoric acid
DOI: 10.1134/S1070363216080132
Silacyclohexanes containing phenyl group and/or
halogen atoms as substituents at the silicon atom are of
interest from the synthetic point of view due to the
possibility of further Si-functionalization via substitu-
tion of the halogen atom by the action of various
nucleophiles or via the Si–Ph bond splitting by
electrophiles [1–3]. Moreover, these compounds are of
special interest for conformational analysis issues: the
conformational preference of the axial or equatorial
conformers of sila(hetero)cyclohexanes, in contrast to
their carbon analogs, is determined mainly by
electronic rather than by steric factors ([4]). The data
on 1-aryl-1-halo-1-silacyclohexanes has been limited
to the only representative, 1-phenyl-1-chloro-1-
silacyclohexane, that has been obtained as an
intermediate [5]. In view of the above, in this work we
investigated the possibility of 1-phenyl-1-Х-1-sila-
cyclohexanes C H Si(Ph)X (X = F, Cl, or Br) prepara-
silicon under the action of various reagents. For example,
1-phenyl-1-chloro-1-silacyclohexane was prepared from
(phenyl)trichlorosilane and dimagnesium 1,5-dibromo-
pentane via the known procedure [6].
Ph
MgBr
MgBr
+
PhSiCl3
Si
(1)
−2MgBrCl
Cl
1
Slow addition of the reagents at high dilution under
argon atmosphere afforded the target product 1 in 74%
yield. Its structure was confirmed by the data of IR,
1
13
29
Н, С, and Si NMR spectroscopy, and mass
13
29
spectrometry. According to the С and Si NMR
spectroscopy data, the product contained up to 20% of
admixture that could not be separated off after several
distillations. As judged from the very close signals of
5
10
13
the admixture and the major product in the С NMR
tion and compared the methods of their synthesis.
spectrum, the presence of the peak with m/z 366 in the
Silacyclohexanes with mentioned substituents at
silicon atom can be synthesized using the Grignard
reagent prepared from 1,5-dibromopentane in the
reaction with the properly substituted silanes and, if
required, further substitution of functional groups at
mass spectrum, and absorption in the IR spectrum at
–
1
1074 cm (shoulder), the admixture could be identified
as (1,1'-phenyl-1,1'-silacyclohex-1-yl)disiloxane 2.
However, the suggestion was inconsistent with the
2
9
29
presence of the Si NMR signal at 15.00 ppm (the Si
1
854

1
-PHENYL-1-HALO-1-SILACYCLOHEXANES
1855
chemical shift in the spectrum of compound 1 was
were very close to those of the admixture, still non-
identified.
2
9
1
6.33 ppm), whereas for disiloxanes the Si chemical
shifts are registered in a stronger field, down to
7 ppm.
In view of the obtained result, we attempted an
alternative method for synthesis of compound 1, chlorina-
tion of the Si–H bond in 1-phenyl-1-chloro-1-silacyclo-
hexane 3 under the action of N-chlorosuccinimide
widely used in laboratory practice [8–10].
–
Disiloxane 2 was synthesized independently by the
2
9
alkaline hydrolysis of compound 1 [7], and its Si
1
3
chemical shift was –6.53 ppm, although the С signals
O
O
Ph
Ph
Si
+
N Cl
O
Si
+
NH
O
(2)
H
Cl
3
1
The thus prepared product 1 was identical to that
prepared via the Grignard reaction but did not contain
the admixture of siloxane. The reaction performed by
the standard procedure (on cooling to 0°C) resulted in
only 30% conversion. The yield of product 1 was
increased to 66% by carrying out the reaction at room
temperature.
of the used method was the presence of SbCl3
admixture in the product, as evidenced by the presence
of [SbCl3] peak with m/z 226 and characteristic
+
isotopic distribution in the mass spectrum. In view of
the further intended investigation of compound 4 by
gas electron diffraction, that admixture could com-
plicate the results interpretation because of strong
dissipation of radiation on the antimony atom.
Therefore, we synthesized product 4 via the exchange
reaction of compound 1 with 40% hydrofluoric acid.
Pure product 4 was obtained in 70% yield.
Synthesis of compounds containing the Si–F bond
can be realized via the exchange of chlorine with
fluorine in the corresponding chlorosilanes by the
action of different reagents (HF or metal fluorides [7,
8
, 11]). The highest hydrolytic stability of fluoro-
Bromosilanes are hydrolyzed easier that the
corresponding chlorinated- and fluorinated derivatives
silanes as compared to other halosilanes is due to high
energy of the Si–F bond. We prepared the unknown
earlier 1-phenyl-1-fluoro-1-silacyclohexane 4 via fluorina-
tion of 1-phenyl-1-chloro-1-silacyclohexane with anti-
mony trifluoride using the adopted method of 1-fluoro-
[8]; therefore, the former are hardly accessible.
Moreover, their high instability in the presence of air
moisture requires special precautions, complicating the
study of these compounds by physico-chemical and
spectral methods. We investigated the possibility of 1-
phenyl-1-bromo-1-silacyclohexane 5 synthesis by
analogy with 1-phenyl-1-chloro-1-silacyclohexane 1,
using N-bromosuccinimide as the brominating agent
1-methyl-1-silacyclohexane synthesis [12].
Ph
Ph
SbF3
Si
Si
(3)
F
Cl
1
4
[13]. Insolubility of the product of its transformation
The synthesis was performed in the absence of
solvent using dry reagents under argon atmosphere on
cooling (3–5°С). The target product was isolated in
(succinimide) in organic solvents could facilitate the
target product isolation. The reaction of 1-phenyl-1-
silacyclohexane with N-bromosuccinimide was carried
out in methylene chloride at room temperature under
dry argon atmosphere using thoroughly dried
chemicals.
9
4% yield. The structure of compound 4 was con-
1
13
19
29
firmed by means of IR, Н, С, F, and Si NMR
spectroscopy and mass spectrometry. The disadvantage
O
O
Ph
Ph
Br
Ph Ph
Si
+
N Br
O
Si
+
Si
Si
+
NH
O
(
4)
H
O
3
5
2
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 8 2016

1
856
SUSLOVA, SHAINYAN
13
29
–1
Chemical shifts in the С and Si NMR spectra of compounds
, 2, 5
ν(Si–O–Si) band at 1074 cm in the IR spectrum as
13
1
well as the signals of product 5 in the C NMR spectrum.
2
,6
3,5
4
29
Compound
C
C
C
Si
1
-Phenyl-1-bromo-1-silacyclohexane 5 has been
1
15.65 23.61 29.29 16.13
mentioned in the literature as a synthon for preparation
of drugs [14, 15], but neither its spectral nor any other
parameters have been given.
Admixture in reaction (1) 16.07 23.61 29.23 15.00
5
2
16.06 23.80 29.23 14.98
15.05 24.39 29.88 –6.53
In summary, we prepared for the first time the hyd-
rolytically stable 1-phenyl-1-fluoro-1-silacyclohexane
using two methods. 1-Phenyl-1-chloro-1-silacyclo-
hexane was synthesized by the reaction of phenyltri-
chlorosilane with dimagnesium 1,5-dibromoethane and
by chlorination of 1-phenyl-1-silacyclohexane with N-
chlorosuccinimide. We failed to prepare 1-phenyl-1-
bromo-1-silacyclohexane in pure form because of its
high hydrolytic instability.
The reaction mixture was treated by vacuum
distillation of the reaction mixture after filtration using
reverse Schott filter. According to chromato–mass
spectrometry data, the product isolated in 60% yield
contained 11% of the unreacted starting compound 3
m/z 176), 18% of the target product 5 (m/z 254 for
Br) and 62% of siloxane 2 (m/z 366). The high
(
7
9
content of siloxane was confirmed by the presence of a
EXPERIMENTAL
–1
broad band at 1069 cm in the IR spectrum of the
obtained mixture, typical of the ν(Si–O–Si) vibrations
in siloxanes. The formation of the desired product 5
was confirmed by the elemental analysis (found
1
13
19
29
Н, С, F, Si NMR spectra were registered
using a Bruker AVANCE 400 (400, 100, 376, and
0 MHz, respectively) instrument in CDCl solution.
8
3
IR spectra were recorded using a Bruker Vertex 70
instrument. Electron impact mass spectra (70 eV) were
recorded with a GCMS-QP5050A Shimadzu mass
spectrometer with quadruple mass analyzer. Column
2
2.75% of Br, calculated 31.33%). The difference in
the composition of the reaction products as determined
by different analytical methods was apparently due to
gradual hydrolysis of bromide 5 into siloxane 2.
chromatography was performed on silica Merck
Analysis of the products of reaction (4) by NMR
spectroscopy showed the full or almost full coin-
cidence of the С and Si NMR signals with those for
the products of reaction (1) and of disiloxane 2, except
1
(
Geduran). The reactions were followed by H NMR
and TLC on 60 F-254 silica plates. Solvents were
purified and dried by conventional methods and stored
over molecular sieves 4A.
1
3
29
2
9
for the Si NMR signals (see the table).
1-Phenyl-1-chloro-1-silacyclohexane (1). а. A solu-
As follows from the Table, the spectra of the ad-
mixture in 1-phenyl-1-chloro-1-silacyclohexane 1 and
of 1-phenyl-1-bromo-1-silacyclohexane 5 are identical.
That suggested that reaction (1) was accompanied by
trans-halogenation, and the brominated analog of
compound 1, heterocycle 5, was formed. The Si
NMR spectroscopy data confirmed the absence of
siloxane 2 in the freshly obtained products. Its later
detection by the methods of IR spectroscopy and mass
spectrometry was apparently due to hydrolysis of
product 5 and formation of the siloxane in contact with
air during the measurements.
tion of dibromopentane (15 g, 0.065 mol) in 130 mL of
anhydrous diethyl ether was added dropwise to 3.53 g
(
0.074 mol) of activated magnesium powder in 20 mL
of anhydrous diethyl ether under argon atmosphere
over 4 h; the mixture was stirred for 3 h and kept
overnight under argon at room temperature. An excess
2
9
(
0.065 mol) of two-phase mixture of the Grignard
reagent was added over 3 h to 12.27 g (0.058 mol) of
phenyltrichlorosilane in 150 mL of diethyl ether, and
the reaction mixture was refluxed for 5 h. After that,
1
00 mL of hexane was added, the precipitate was
filtered off and washed twice with diethyl ether. After
removal of the solvents (45 mmHg) and vacuum
distillation, 9.64 g (74%) of 1-phenyl-1-chloro-1-sila-
cyclohexane 1 was obtained, bp 129–132°С (1 mmHg).
Performing the reaction on cooling did not reduce
the content of the siloxane in the product mixture, but
decreased the conversion to 20%. When the reaction
was carried out at 3°С, the vacuum-distilled reaction
mixture contained, along with the starting compound
1
3
29
According to С and Si NMR data, the product
contained up to 20% of an admixture. IR spectrum
–
1
3
, the target product 5 and siloxane 2, as evidenced by
(thin film, ν, cm ): 3075, 2927, 1431, 1119, 532–516.
–
1
1
the presence of the ν(Si–H) band at 2113 cm and
Н NMR spectrum, δ, ppm: 1.12–1.50 m (5Н,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 8 2016

1
-PHENYL-1-HALO-1-SILACYCLOHEXANES
1857
4
4
2,6
3,5
4
SiСН +H ), 1.74–1.85 m (1H, H ), 1.86–2.08 m (4Н,
δ , ppm: 15.05 (C ), 24.39 (C ), 29.88 (C ), 127.69
С
2
,5
A
B
3
m,p
p
m
o
i
29
СН ), 7.44–7.55 m (3Н, H ), 7.69–7.76 m (2Н,
H ). С NMR spectrum, δ , ppm: 15.65 (C ), 23.61
C ), 29.29 (C ), 128.08 (C ), 130.42 (C ), 133.38
C ), 134.83 (C ). Si NMR spectrum, δ : 16.13 ppm.
The NMR data coincided with the reference data [5].
Mass spectrum, m/z (I , %): 210 (18) [M], 167 (12)
(C ), 129.35 (C ), 133.42 (C ), 138.22 (C ). Si NMR
spectrum, δ : –6.53 ppm. Mass spectrum, m/z (I , %):
366 (18) [M], 288 (100) [M – Ph], 260 (82).
2
o
13
2,6
С
Si
rel
3
,5
4
p
m
(
(
o
i
29
Si
1
-Phenyl-1-fluoro-1-silacyclohexane (4). а. 0.86 g
4.8 mmol) of SbF was added at 3°С to 2.04 g
9.6 mmol) of 1-phenyl-1-chloro-1-silacyclohexane 1.
The reaction mixture was stirred for 2 h at 5°С, then
gradually heated to room temperature, and stirred for
h. Vacuum distillation gave 1.76 g (94%) of
compound 4, bp 115–119°С (1 mmHg). IR spectrum
thin film, ν, cm ): 3072, 2924, 1429, 1121, 909–840.
Н NMR spectrum, δ, ppm: 0.90–1.04 m (2Н, Н ),
.06–1.18 m (2Н, НB ), 1.39–1.51 m (1Н, Н ), 1.60–
.74 m (1Н, Н ), 1.78–1.96 m (4Н, Н ), 7.40–7.52 m
3Н, H ), 7.61–7.67 m (2Н, H ). С NMR spectrum,
δ , ppm: 13.27 (d, C , J = 12.9 Hz), 24.06 (C ),
29.51 (C ), 128.18 (C ), 130.59 (C ), 133.48 (C ),
134.76 (d, C , J = 15.9 Hz). Si NMR spectrum, δ :
(
(
3
rel
[
1
M – C H ], 141 (36) [PhSiHCl], 132 (100) [M – Ph],
3 7
17 (16) [132 – CH ], 105 (15) [PhSi], 63 (42) [SiCl].
3
Spectral characteristics of the admixture: IR spectrum
thin film, ν, cm ): 3075, 2927, 1431, 1119, 1074 (sh.
SiOSi), 532–516. Н NMR spectrum, δ, ppm: 1.18–
.00 m (10Н, СН ), 7.49–7.91 m (5Н, Ph). С NMR
spectrum, δ , ppm: 16.07 (C ), 23.62 (C ), 29.23
C ), 128.54 (C ), 130.51 (C ), 133.52 (C ), 134.59
C ). Si NMR spectrum, δ : 15.00 ppm. Mass spec-
6
–
1
(
1
–1
(
1
3
2
1
2,6
2
2
,6
3,5
A
С
2,6
4
1
1
(
4
p
m
o
A
(
(
4
3,5
i
29
B
Si
m,p
o
13
trum, m/z (I , %): 366 (18) [M], 288 (100) [M – Ph].
2,6
3,5
rel
С
CF
4
m
p
o
b. A suspension of 2.53 g (0.018 mol) of N-chloro-
succinimide in 10 mL of anhydrous СН С1 was added
i
29
2
2
CF
Si
1
9
portionwise over 1 h under argon atmosphere to a
solution of 3.038 g (0.017 mol) of 1-phenyl-1-sila-
cyclohexane 3 in 3 mL of anhydrous methylene
chloride. The reaction mixture was stirred at room
temperature for 6 h, methylene chloride was removed
under reduced pressure, 10 mL of pentane was added,
and the precipitate filtered off after sedimentation.
After removal of the solvents, vacuum distillation gave
.39 g (66%) of compound 1, bp 139–142°С (1 mmHg).
IR and NMR spectroscopy as well as chromato-mass
spectrometry data corresponded to the reference data
5] and to the data obtained for the product prepared
via method а. Found, %: С1 16.70. C H ClSi.
14.94 ppm (d, JSiF = 289.2 Hz). F NMR spectrum, δ ,
ppm: –170.5 (t, JFSi = 289.9 Hz, JHF = 11.8 Hz). Mass
F
spectrum, m/z (I , %): 194 (29) [M], 138 (42), 125
rel
(69), 116 (100) [M – Ph], 101 (22), 91 (35).
b. 1-Phenyl-1-chloro-1-silacyclohexane 1 (2 g, 9.5
mmol) was added dropwise to 10 mL of 40% HF and
stirred for 1.5 h at room temperature. The organic layer
was separated and dried over KF. Vacuum distillation
at 110°С (1 mmHg) gave 1.288 g (70%) of product 4.
Its spectral data were similar to those reported for
method a. Found, %: С 67.60; H 7.71; F 10.01.
C H FSi. Calculated, %: C 67.94; H 7.72; F 9.78.
2
[
1
1
15
11
15
Calculated, %: Cl 16.84.
1,1'-Phenyl-1,1'-silacyclohex-1-yl)disiloxane (2).
.64 g (0.011 mol) of KОН in 10 mL water and 1.15 g
0.011 mol) of triethylamine were added dropwise at
room temperature and stirring to 1.20 g (5.7 mmol) of
-phenyl-1-chloro-1-silacyclohexane 1 in 5 mL of
methylene chloride. The reaction mixture was stirred
for 2 h and kept overnight; the organic layer was
separated, washed with water and salt solution, and
1-Phenyl-1-bromo-1-silacyclohexane
(5).
A
suspension of N-bromosuccinimide (1.38 g, 7.7 mmol)
in 5 mL of anhydrous methylene chloride was added
portionwise over 40 min under dry argon atmosphere
at room temperature to a solution of 1.37 g (7.7 mmol)
of 1-phenyl-1-silacyclohexane 3 in 3 mL of anhydrous
methylene chloride. The reaction mixture was stirred
for 5 h at room temperature; succinimide was
precipitated with pentane (4 mL), and the mixture was
filtered through a reverse Schott filter. After removal
of the solvents at reduced pressure, vacuum distillation
gave 1.06 g (60%) of the product, bp 126–130°С
(
0
(
1
dried over CaCl . After removal of the solvent, 0.46 g
2
(
44%) of crude product was obtained as dense color-
less oil that was purified by column chromatography
(
1 mmHg) According to chromato-mass spectrometry
data, the distillate contained 62% of siloxane 2, 18% of
-phenyl-1-bromo-1-silacyclohexane 5, and 11% of 1-
on silica (hexane, hexane–ether, 9 : 1, R = 0.86). IR
f
–
1
spectrum (thin film, ν, cm ): 3070, 2918, 1448, 1115,
1
1
1
0
070 (SiOSi), 517. Н NMR spectrum, δ, ppm: 0.88–
4
phenyl-1-silacyclohexane 3.
.99 m (4Н, SiСН ), 1.41–1.51 m (1H, H ), 1.51–1.62
2
A
4
3,5
m (1H, H ), 1.66–1.86 m (4Н, СН ), 7.35–7.45 m
3Н, H ), 7.58–7.63 m (2Н, H ). С NMR spectrum,
1-Phenyl-1-bromo-1-silacyclohexane (5). IR spec-
B
2
m,p
o
13
–1
(
trum (thin film, ν, cm ): 3069, 2918, 2113 (SiH),
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 8 2016

1
858
SUSLOVA, SHAINYAN
1
1
428, 1116, 1069 (SiOSi), 532–516. Н NMR spec-
vol. 68, no. 1, p. 114. doi 10.1016/j.tet.2011.10.082.
trum, δ, ppm: 1.24–1.93 m (10Н, СН ), 7.46–7.67 m
6. West, R., J. Am. Chem. Soc., 1954, vol. 76, no. 23,
2
13
2,6
(
5Н, Ph).3 С NMR spectrum, δ , ppm: 16.06 (C ),
p. 6012.
С
,5
4
p
m
2
1
1
3.80 (C ), 29.23 (C ), 128.29 (C ), 130.54 (C ),
7. Mutachi, M., Nittoli, T., Guo, L., and Sieburth, S.McN.,
o
i
29
J. Am. Chem. Soc., 2002, vol. 124, no. 25, p. 7363. doi
33.53 (C ), 134.56 (C ). Si NMR spectrum, δ :
Si
7
9
1
0.1021/ja026158w.
4.98 ppm. Mass spectrum, m/z (to Br) (I , %): 254
rel
8. Kunai, A. and Ohshita, J., J. Organomet. Chem., 2003,
(
10) [M], 176 (100) [M – Ph], 105 (87) [PhSi].
vol. 686, nos. 1–2, p. 3. doi 10.1016/S0022-328X(03)
0
0254-7.
ACKNOWLEDGMENTS
9
. Pestunovich, V.A., Kirpichenko, S.V., Lazareva, N.F.,
Albanov, A.I., and Voronkov, M.G., J. Organomet.
Chem., 2007, vol. 692, no. 11, p. 2160. doi 10.1016/
j.organchem.2007.01.035.
This work was performed with the use of equip-
ment of the Baikal Analytical Center for Collective
Usage, Siberian Branch of Russian Academy of
Sciences. The authors are grateful to S.V. Kirpichenko
for providing literature sources and discussion of the
results.
1
1
1
0. Varaprath, S. and Stutts, D.H., J. Organomet. Chem.,
007, vol. 692, no. 10, p. 1892. doi 10.1016/
2
j.organchem.2006.12.032.
1. Kirpichenko, S.V. and Albanov, A.I., J. Organomet.
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2. Wallevik, S., Bjornsson, R., Kvaran, A., Jonsdottir, S.,
Girichev, G., Giricheva, N., Hassler, K., and Arnason, I.,
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