Russian Journal of General Chemistry, Vol. 74, No. 6, 2004, pp. 882 884. Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 6, 2004,
pp. 956 958.
Original Russian Text Copyright
2004 by Basenko, Gebel’, Boyarkina, Voronkov.
Reaction of Organylchlorosilanes with Dimethyl Sulfoxide
in the Presence of Octamethyltrisiloxane
S. V. Basenko, I. A. Gebel’, E. V. Boyarkina, and M. G. Voronkov
Favorskii Irkutsk Institute of Chemistry, Siberian Branch,
Russian Academy of Sciences, Irkutsk, Russia
Received May 7, 2002
Abstract Dichloro(methyl)(vinyl)silane reacts with DMSO in the presence of octamethyltrisiloxane to
form cyclooligomethyl(vinyl)siloxanes(MeViSiO)n (n = 3 6). The reaction involves disproportionation of
octamethyltrisiloxane into hexamethyldisiloxane and decamethyltetrasiloxane. Along with the latter two
products, insertion products of methyl vinyl silanone into both permethyloligosiloxanes were identified. Alkyl-
trichlorosilanes RSiCl3 (R = Me, Et) react with DMSO in the presence of octamethyltrisiloxane to form cyclic
oligoalkyltrichlorosiloxanes (RClSiO)m (m = 3 6).
Previously we showed that the reaction of dior-
ganyldichloro- and organyltrichlorosilanes with
DMSO in a hexamethyldisiloxane (I) medium is a
convenient synthetic route to linear and cyclic organyl-
(trimethylsiloxy)siloxanes [1, 2].
(1:1:3 reagent molar ratio), the yield of cyclomethyl-
(vinyl)siloxanes IV VII is almost the same.
Under the reaction conditions, trisiloxane II under-
goes disproportionation into disiloxane I and de-
camethyltetrasiloxane (X). Neither MeVinSiCl2 nor
DMSO taken separately induce disproportionation of
compound II.
The major products of reaction (1) between di-
chloro(methyl)(vinyl)silane with DMSO in the
presence of octamethyltrisiloxane (II) that serves for
trapping the intermediate methyl vinyl silanone (III),
at 20 C and a 1:1:1 reagent molar ratio are cyclo-
methyl(vinyl)siloxanes (MeViSiO)n (IV VII, n = 3
6) in a total yield of 75 80%. Therewith, the yield of
insertion products of methyl vinyl silanone into tri-
siloxane II, namely 1,1,1,3,5,5,7,7,7-nonamethyl-3-
vinyltetrasiloxane (VIII) and 1,1,1,3,5,7,7,9,9,9-de-
camethyl-3,5-divinylpentasiloxane (IX), is as low
as 3 5%.
2Me3SiOSiMe2OSiMe3
II
Me3SiOSiMe3 + Me3SiOSiMe2OSiMe2OSiMe3. (4)
I
X
Siloxanes I and X were isolated and characterized
by GC MS, along with insertion products of silanone
III into disiloxane I [1,1,1,3,5,5,5-heptamethyl-3-
vinyltrisiloxane (XI), 1,1,1,3,5,7,7,7-octamethyl-3,5-
divinyltetrasiloxane (XII), 1,1,1,3,5,7,9,9,9-nona-
methyl-3,5,7-trivinylpentasiloxane (XIII)] and into
decamethyltetrasiloxane [1,1,1,3,5,5,7,7,9,9,9-unde-
camethyl-3-vinylpentasiloxane (XIV)].
CH3(CH2=CH)SiCl2 + OS(CH3)2
(1)
(2)
[CH3(CH2=CH)Si=O] + S(CH2Cl)CH3,
HCl
III
n[MeVinSi=O]
III
(MeVinSiO)n,
IV VII
I + III
Me3SiO(MeVinSiO)nSiMe3,
(5)
XI XIII
m[MeVinSi=O] + Me3SiOSiMe2OSiMe3
II
n = 1 (XI), 2 (XII), 3 (XIII).
III + Me3SiOSiMe2OSiMe2OSiMe3
Me3SiOSiMe2O(MeVinSiO)mSiMe3,
(3)
X
VIII, IX
Me3SiOSiMe2OSiMe2O(MeVinSiO)SiMe3.
(6)
n = 3 (IV), 4 (V), 5 (VI), 6 (VII); m = 1 (VIII), 2 (IX).
XIV
Reaction (2) between MeVinSiCl2 and DMSO can
occur in the absence of trisiloxane II [1], and the yield
of compounds IV VII is slightly higher. At higher
concentrations of trisiloxane II in the reaction mixture
Insertion products XI XIII we also identified
earlier in the reaction of MeVinSiCl2 with DMSO and
disiloxane I [1].
1070-3632/04/7406-0882 2004 MAIK Nauka/Interperiodica