Si-disubstituted diallylsilanes in homolytic thiylation and electrophilic fragmentation reactions

Article abstract of DOI:10.1134/S1070363208090065

Approaches to Si-disubstituted 1-thia-5-silacyclooctanes based on homolytic addition of hydrogen sulfide to diallylsilanes R₂Si(CH ₂CH=CH₂)₂ and on intramolecular cyclization of Si-disubstituted (allyl)(γ-sulfanylpropyl)silanes have been studied. In the former case the reactivity of the silanes decreases in the order R = MeO > F > Me > Ph, whereas in the latter case the reactivity order is slightly different: Me > MeO ≈ F ? Ph. The reactions of diphenyl-and dimethyldiallylsilanes with the complex BF₃?2AcOH occur in a different manner: The former involves rearrangement to form fluoro(2-methylpent- 4-enyl)diphenylsilane, while the latter, elimination of the two allyl groups to fluorodimethylsilane and propene.

Full text of DOI:10.1134/S1070363208090065

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 9, pp. 1675–1681. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © E.N. Suslova, A.I. Albanov, B.A. Shainyan, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 9, pp. 1442–1448.
Si-Disubstituted Diallylsilanes
in Homolytic Thiylation
and Electrophilic Fragmentation Reactions
E. N. Suslova, A. I. Albanov, and B. A. Shainyan
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: bagrat@irioch.irk.ru
Received May 6, 2008
Abstract―Approaches to Si-disubstituted 1-thia-5-silacyclooctanes based on homolytic addition of hydrogen
sulfide to diallylsilanes R2Si(CH2CH=CH2)2 and on intramolecular cyclization of Si-disubstituted (allyl)(γ-
sulfanylpropyl)silanes have been studied. In the former case the reactivity of the silanes decreases in the order
R = MeO > F > Me > Ph, whereas in the latter case the reactivity order is slightly different: Me > МеО ≈ F >>
Ph. The reactions of diphenyl- and dimethyldiallylsilanes with the complex BF3·2AcOH occur in a different
manner: The former involves rearrangement to form fluoro(2-methylpent-4-enyl)diphenylsilane, while the
latter, elimination of the two allyl groups to fluorodimethylsilane and propene.
DOI: 10.1134/S1070363208090065
Diallylsilanes are of interest as precursors of eight-
membered heterocycles, thiasilacyclooctanes and their
sulfur oxidation products. The stereochemistry of
heterocycles of this type is to a large extent determined
by the presence of the two heteroatoms different in
nature, relative position, and possibility to interact with
each other. For example, in eight-membered cycles,
such as trithia- and thia(dioxa)germacyclooctanes I
[1], 1-thia-4,6-dioxa-5-silacyclooctane and its analogs
In this connection it was of interest to investigate
the possibility of preparation and the structure of
thiasilacyclooctanes with electron-acceptor sub-
stituents at the silicon atom, in particular, 5,5-difluoro-
1-thia-5-silacyclooctane F2Si[(CH2)3]2S and its S-
functional derivatives.
The syntheses of 5,5-dimethyl- and 5,5-diphenyl-1-
thia-5-silacyclooctanes R2Si[(CH2)3]2S by hydrogen
sulfide addition to the corresponding diallylsilanes
R2Si(CH2CH=CH2)2 at –78°С and UV irradiation
(yield 10–25%) [5, 6] of 5,5-diethyl-1-thia-5-
silacyclooctane by diethylsilane addition to diallyl
sulfide followed by cyclization of the γ-adduct [7]
have been reported. These and other syntheses of
silicon-containing diheterocyclic compounds have
been recently reviewed [8].
II [2, 3],
chelate cycles with intramolecular
coordination S→Si(Ge) (I) or S=О→Si (II) bond
stabilizing the boat conformation can form, as proved
by X-ray diffraction analysis. Theoretical studies ([4]
and references therein) showed that in Si-halogenated
1,4-silathiane S-oxides III (X, Y = F, Cl, Br), too,
forma-tion of five-membered chelate cycles with the
coordination S=О→Si bond is also possible.
R
R
X
O
O
M
Si
Si
R
S
R
S
O
S
E
O
Y
E
O
III
I
II
M = Si, Ge; E = O, S.
1675

1676
SUSLOVA et al.
We earlier prepared 5,5-difluoro- and 5,5-
dimethoxy-1-thia-5-silacyclooctanes F2Si[(CH2)3]2S
and (МеО)2Si[(CH2)3]2S [9] and 5,5-dimethyl-1-thia-5-
silacyclooctane Me2Si[(CH2)3]2S [10] by homolytic
thiylation of the corresponding diallylsilanes with
gaseous H2S (yield ~30%). We performed GC and
NMR monitoring of this reaction with different
diallylsilanes in cyclohexane and without a solvent.
Apart from the starting silanes, we detected in the
reaction mixture thiols and cyclic and linear sulfides.
CH2CH=CH2
(CH2)3SH
CH2CH2CH2
[R2Si
(CH2)3
]2S
H2S
R2Si
R2Si
R2Si
+
S
+
(1)
hν
CH2CH=CH2
CH2CH=CH2
IV_VII
CH2CH=CH2
VIII_XI
CH2CH2CH2
XII_XV
XVI_XVIII
R = F (IV, VIII, XII, XVI); MeO (V, IX, XIII); Ph (VI, X, XIV, XVII); Me (VII, XI, XV, XVIII).
cyclohexane for 3 h, 25% of thiol IX was formed at a
50% conversion. The reaction of diallyldifluorosilane
(IV) in cyclohexane, too, gave more thiol VIII
(VIII:XII 2:1), and it could be isolated pure. In the
reaction of hydrogen sulfide with diallyldimethylsilane
in cyclohexane, the conversion drops so drastically that
only 8–10% of thiol XI and trace amounts of thiasila-
cyclooctane XV are formed. The yields of thiasila-
cyclooctanes XII–XV at various reaction conditions
are given in Table 1.
In the absence of solvent after 3 h at 50°С, the
conversion of silanes IV–VII was 70–80% for R = F,
MeO and ~40% (60% in 6 h) for R = Me.
Diallyldiphenylsilane (VI) was found to be even less
active: Its conversion was 20, 50, and 80% after 3, 7
and 13 h, respectively. The fraction of sulfides XVI–
XVIII in the reaction products reached 20% (see also
[10]).
Intramolecular cyclization of thiols VIII–XI pro-
ceeds regioselectively, in accordance with published
data [5, 6, 10, 11]. The total content of thiols and
thiasilacyclooctanes under these conditions is 52–55%
(R = F, 3 h, VIII:XII = 1:1), 20% (R = Me, 3 h,
XI:XV = 3:1), 32% (R = Me, 6 h, XI:XV = 2:1), 17%
(R = Ph, 3 h, X:XIV = 100:0), 38% (R = Ph, 7 h,
X:XIV = 9:1), and 60% (R = Ph, 13 h, X:XIV = 3:1).
Further increase of the reaction time (R = Ph) leads
only to an increase of the content of oligomerization
products. The isolated products were thiol X in 32%
yield and thiasilacyclooctane XIV in 11% yield.
Therefore, the reactivity of diallylsilanes IV–VII in
the photochemical heterocyclization reaction (1) de-
creases in the order R = MeO > F > Me > Ph.
To increase the yield of thiasilacyclooctanes, we
studied alternative synthetic approach involving
intramolecular cyclization of independently syn-
thesized thiols VIII–X. This approach was earlier
suggested for thiol XI [5, 6, 12]. Thiols VIII–X were
prepared by different methods to provide their highest
yields. Thus thiol X was obtained in 60% yield by
radical addition of thioacetic acid to diallyldiphenyl-
silane with subsequent saponification with sodium
hydride in ethanol.
With R = MeО, thiasilacyclooctane XIII was
isolated in 23% yield; thiol (IX) could not be detected
by GC. However, when the reaction was performed in
(CH2)3SCOMe
CH2CH=CH2
(CH2)3SCOMe
MeCOSH
R2Si
R2Si
R2Si
+
hν
(CH2)3SCOMe
XXII_XXIV
CH2CH=CH2
IV_VI
CH2CH=CH2
XIX_XXI
R = Ph
NaH/EtOH
hν
XII_XV
VIII_XI
(2)
R = Ph (XIX, XXII); F (XX, XXIII); MeO (XXI, XXIV).
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Si-DISUBSTITUTED DIALLYLSILANES IN HOMOLYTIC THIYLATION
1677
Table 2. Photochemical cyclization of thiols R2Si(СН2СН=
СН2)(CH2CH2CH2SH) into thiasilacyclooctanes R2Si(CH2·
CH2CH2)2S
Table 1. Reaction of diorganyldiallylsilanes R2Si(CH2CH=
CH2)2 with hydrogen sulfide
Yield of thiasilacyclooctane
R
Yield of the cycle, %
R
without solvent
in cyclohexane
after 1.5 h
after 3 h
F
28
16
24
5
F
16
10
27
–
24
23
33
–
MeO
Me
30
MeO
Me
Ph
13 (25%, 6 h)
Ph
0 (11%, 13 h)
–
Mono- and dithioacetates XIX and XXII are easily
separated by vacuum distillation. The intermediate
mono- and dithioacetates were also prepared with
diallyldifluoro- and diallyldimethoxysilanes, but their
saponification was complicated by hydrolytic cleavage
of the Si–F or Si–O bond. Therefore, thiol VIII was
isolated by preparative GC from the reaction of silane
IV with hydrogen sulfide, and thiols IX and XI were
synthesized in 12 and 43% yields, respectively, by
decomposition with dry ammonia of thiuronium salts
prepared from the corresponding 3-chloropropylsilanes
and thiourea (data of this work and ref. [11]).
It follows from a comparison of the results of
investigation of reactions (1) and (2) that the one-step
reaction of diallylsilanes with hydrogen sulfide is the
most suitable for preparing thiasilacyclooctanes with
labile substituents at the silicon atom, in particular,
with fluorine atoms. However, for this synthesis one
needs hardly accessible diallyldifluorosilane. There-
fore, taking into account the reported cleavage of the
Si–Ph bond in the SiR2Ph and SiRPh2 groups by the
action of the complexes BF3·2AcОH (XXV) and
HBF4·OEt2 to form compounds containing SiFR2 and
SiF2R groups [13–15], we tried to convert
diallyldiphenylsilane (VI) into diallyldifluorosilane
(IV) in order to cyclize the latter into the target 5,5-
difluoro-1-thia-5-silacyclooctane (XII). It should be
noted that the allyl group in allyltrimethylsilanes
R3SiCH2CH=CHR is readily eliminated under the
action of various electrophilic reagents, including
fluorine-containing ones [16–18]. However, a priori it
was difficult to predict the reaction pathway of
complex XXV with diallyldiphenylsilane (VI) pos-
sessing two groups capable of elimination: allyl and
phenyl. It turned out that neither silane IV nor its
precursor, diallyl(fluoro)phenylsilane, nor any
products of elimination of one or two allyl groups are
formed; instead, we obtained a rearrangement product,
The last step of reaction (2) (cyclization of thiols
into thiasilacyclooctanes) was performed under UV
irradiation of 5% solutions of thiols in cyclohexane at
55°С. From GC, the yields of thiacyclooctanes from
thiols VIII, IX, and XI after 1.5 h were about 70%
(per reacted thiol); however, because of strong tarring,
the isolated yields of thiasilacyclooctanes XII, XIII,
and XV were 18, 10 and 27%, respectively. Prolonga-
tion of the reaction time to 3–5 h allows to the yields to
be increased 24–33%. Thiol Х fails to cyclize under
these conditions. Lowering the temperature to 0°С
completely stops the reaction, while UV irradiation in
the presence of benzoyl peroxide at 50°С leads, from
1Н and 29Si NMR data, to formation of as little as 4–
5% of heterocycle XIV.
fluoro(2-methylpent-4-enyl)diphenylsilane
(XXVI)
was obtained in 63% yield [19]. A mechanism of its
formation was suggested, which involved the
rearrangement of the carbocation with cleavage of the
Si–Csp3 bond by the SE' allylic substitution mechanism
and addition of the fluoride ion to the resulting silyl
cation [19].
The results of photochemical cyclization of organo-
silicon thiols into thiasilacyclooctanes are summarized
in Table 2. As follows from these data, the reactivity
order in this case is slightly different from that in
reaction (1): Me > МеО ≈ F >> Ph.
+
_
_
_
Ph
Ph
CH2 CH CH3
Ph
Ph
CH2 CH=CH2
H+
Si
Si
_
_
CH2 CH=CH2
CH2 CH=CH2
Ph
Ph
CH CH2
Ph
Ph
CH2 CH CH2
F _
+
Si
CH2 CH
CH3
Si
CH2 CH CH2
(3)
CH3
XXVI
F
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SUSLOVA et al.
A direct analog of reaction (3) is the rearrangement
The formation of difluorodimethylsilane is unequi-
vocally proved by the observation in the 19F NMR
of diorganyl(diallyl)silanes into diorganyl(fluoro)(2-me-
thylpent-4-enyl)silanes R2Si(F)CH2CH(Me)CH2CH=
CH2, that occurs as a side process in the reaction of the
former with α,β-unsaturated ketones in the presence of
BF3·OEt2. The yields of these products were 15, 0, and
5% for R = i-Pr, Pr and Ph, respectively [20].
3
spectrum of a septet coupling with JНF 6.1 Hz and a
doublet of septets on 29Si satellites with 1JSiF 290.7 Hz.
Evidence for the formation of propene comes from the
1
observation in the Н NMR spectrum of a doublet of
the methyl group, two doublets of the =CH2 group
with characteristic Jcis and Jtrans coupling constants, and
a multiplet signal of the CH= proton (3:1:1:1), as well
as the corresponding signals in the 13С NMR spectrum.
A similar rearrangement, occurring in parallel with
elimination of propene and formation of diorganyl
(allyl)chlorosilanes, was observed during thermolysis
of
allyl(2-chloropropyl)dimethyl-
and
allyl(2-
Analysis of the pathway and mechanism of the
reaction of diorganyldiallylsilanes with different acids
as a function of the structure of the silane and the
strength of the acid will be the subject of our further
communication.
chloropropyl)diphenylsilanes [21].
CH2CH=CH2
CH2CHClCH3
R
R
CH2CHCH2CH=CH2
Δ
R2Si
Si
CH3
Cl
EXPERIMENTAL
CH2CH=CH2
Cl
The IR spectra were taken on a Specord IR-75
instrument in thin layer and in KBr. The NMR spectra
were recorded on a Bruker DPX 400 spectrometer at
400 (1Н), 100 (13С), 376 (19F), 80 MHz (29Si) for
solutions in CDCl3, references TMS (1Н, 13С, 29Si) and
CCl3F (19F). The electron impact mass spectra (70 eV)
were obtained on Shimadzu GCMS-QP5050A
(compound XII) and Hewlett-Packard HP 5971A
(compounds XIV, XVII) instruments.
_
R2Si
+
+ CH3 CH=CH2
(4)
The product composition crucially depends on the
substituent R: With for R = Me, the reaction by 95%
proceeds as elimination of the allyl group, whereas
with R = Ph, the rearrangement products predominates
(70%) [21].
Taking into account such a strong effect of the
substituent at silicon in allylsilanes on the product
composition, we have studied the reaction of
diallyldimethylsilane (VII) with the complex BF3·
2AcOH. It was earlier shown that silane VII reacts
with trifluoromethanesulfonic acid to form the product
of elimination of one propene molecule, Me2Si
(CH2CH=CH2)OSO2CF3 [22]. It was found that with
complex BF3·2AcOH, too, diallyldimethylsilane (VII)
reacts differently than diallyldiphenylsilane (VI).
Instead of the rearrangement product [see reaction (3)],
only gaseous products of elimination of both allyl
groups, difluorodimethylsilane (XXVII) and propene
(XXVIII), formed and were trapped by bubbling into
CCl4 in a cooled trap.
Photochemical reactions were carried out in quartz
flasks using a DRT-400 UV lamp. Column chromato-
graphy was performed on Silica 60 (Merck).
5,5-Diphenyl-1-thia-5-silacyclooctane (XIV). Dry
hydrogen sulfide was bubbled through 6.93 g of
diphenyldiallylsilane upon UV irradiation at 45–50°С.
1
The reaction was followed by Н and 29Si NMR
spectroscopy by taking out samples every 2–3 h. After
completion, the reaction mixture was repeatedly
extracted with hexane and ether. After removal of the
solvent from the extract, 1.3 g of starting silane VI and
1.98 g of thiol Х was isolated by vacuum distillation.
bp 180–186°С (1 mm Hg), yield 32% (per reacted
silane). The residue insoluble in hexane and ether was
the target 5,5-diphenyl-1-thia-5-silacyclooctane (XIV),
yield 0.73 g (11% per reacted silane). An analytically
pure sample was obtained by column chromatography
on silica, eluents hexane, hexane–ether from 20:1 to
1:1, Rf 0.22, mp 73–74°С. IR spectrum, ν, cm–1: 3060,
CH2CH=CH2
Me2Si
CH2CH=CH2
1
2900, 1580, 1410, 1100, 695. Н NMR spectrum, δ,
VII
ppm: 1.15 m (4Н, SiCH2), 1.55 m (4H, CH2), 2.41 m
(4H, CH2S), 7.34–7.48 m (10H, Ph). 13С NMR
spectrum, δС, ppm: 12.23 (SiCH2), 24.01 (CH2), 35.71
BF3 2AcOH
Me2SiF2 + CH3
CH CH2
XXVIII
(5)
XXVII
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Si-DISUBSTITUTED DIALLYLSILANES IN HOMOLYTIC THIYLATION
1679
(CH2S), 127.97 (Cm), 129.40 (Cp), 134.94 (Cо), 135.63
(C1). 29Si NMR spectrum, δSi, ppm: –6.64. Mass
spectrum, m/z, (Irel, %, ion): 298 (0.1, [M]+·), 256 (5.6,
[M – C3H6]+·), 221 (100, [M – Ph]+), 179 (49, [221 –
C3H6]+), 137 (13, [179 – C3H6]+). The fragmentation of
the molecular ion is similar to that described for 5,5-
dimethyl-1-thia-5-silacyclo-octane [5]. Found, %: C
72.78; H 7.46; S 9.87; Si 9.57. C18H22SSi. Calculated,
%: C 72.48; H 7.38; S 10.74; Si 9.40.
of cyclohexane was added dropwise at 50°С over the
course of 1 h, and the mixture was refluxed for 5.5 h.
After removal of the solvent and vacuum distillation,
2.52 g of monothioacetate ХIХ was isolated with bp
185–187°С (1 mm Hg), yield 56% (per reacted silane),
and 1.21 g of dithioacetate XXII, bp 200–202°С
(1 mm Hg), yield 28%. Analytically pure samples
were obtained by column chromatography on silica,
eluents hexane, hexane–ether, 15:1–5:1.
Cyclization of diorganyldiallylsilanes IV, V, and
VII was performed in a similar way.
The reactions of difluorodiallylsilane and
dimethoxy–diallylsilane with thioacetic acid and
separation of the products was carried out in a similar
way, except that the reaction mixtures were
additionally UV irradiated.
5,5-Difluoro-1-thia-5-silacyclooctane (XII). 1Н
NMR spectrum, δ, ppm: 0.89 m (4Н, SiCH2), 1.85 m
(4H, CH2), 2.54 m (4H, CH2S). 13С NMR spectrum,
δС, ppm: 12.09 t (SiCH2, J 15.7 Hz), 23.09 (CH2),
33.32 (CH2S). 19F NMR spectrum, δ, ppm: –131.11 d
(J 294 Hz). 29Si NMR spectrum, δSi, ppm: –3.08 t (J
291 Hz). Mass spectrum, m/z, (Irel, %, ion): 182 (31,
[M]+·), 140 (100, [M – C3H6]+·), 139 (72, [140 – Н]+),
106 (24, [140 – H2S]+·).
Allyldiphenyl[3-(thioacetoxy)propyl]silane (ХIХ).
Rf 0.3. IR spectrum, ν, cm–1: 3050, 2910, 1690, 1620.
1
1590, 1410, 1120–1100, 690. Н NMR spectrum, δ,
ppm: 1.21 m (2Н, SiCH2), 1.68 m (2H, CH2), 2.15 m
(2H, SiCH2Vi), 2.33 s (3H, CH3), 2.92 m (2H, CH2S),
4.92 m (2H, =CH2), 5.79 m (1H, CH=), 7.39–7.51 m
(10H, Ph). 13С NMR spectrum, δС, ppm: 11.87
(SiCH2), 20.47 (SiCH2Vi), 24.06 (CH2), 30.70 (CH2S),
114.64 (=CH2), 127.97 (Cm), 129.51 (Cо), 133.80
(=CH), 134.95 (Cp), 135.21 (C1), 195.80 (C=O). 29Si
NMR spectrum, δSi, ppm: –9.38. Found, %: C 70.73; H
6.97; S 9.17; Si 7.97. C20H24OSSi. Calculated, %: C
70.55; H 7.10; S 9.41; Si 8.24.
5,5-Dimethoxy-1-thia-5-silacyclooctane (XIII).
1Н NMR spectrum, δ, ppm: 0.79 m (4Н, SiCH2), 1.82
m (4H, CH2), 2.52 m (4H, CH2S), 3.51 s (6Н, МеО)
(coincides with published data [9]). 13С NMR
spectrum, δС, ppm: 10.39 (SiCH2), 23.47 (CH2), 34.09
(CH2S), 50.27 (МеО). 29Si NMR spectrum, δSi, ppm:
–2.21.
Bis[3-(allyldifluorosilyl)propyl] sulfide (XVI). 1Н
NMR spectrum, δ, ppm: 0.95 m (4Н, SiCH2), 1.74 m
(4H, CH2), 1.88 m (4H, SiCH2Vi) 2.53 t (4H, CH2S, J
6.85 Hz), 5.05 d (1H, =CHА, J 9.7 Hz), 5.09 d (1H,
=CHВ, J 17.4 Hz), 5.76 d.d.t (2H, CH=, J 8.0, 9.7, 17.4
Hz). 13С NMR spectrum, δС, ppm: 11.13 t (SiCH2, J
14.57 Hz), 19.79 t (SiCH2Vi, J 14.19 Hz), 21.65
(CH2), 34.55 (CH2S), 117.25 (=CH2), 129.12 (=CH).
19F NMR spectrum, δF, ppm: –139.64 q, (J 306.2,
5.0 Hz). 29Si NMR spectrum, δSi, ppm: –5.03 t (J
306.2 Hz).
Diphenylbis[3-(thioacetoxy)propyl]silane (ХХII).
Rf 0.1. IR spectrum, ν, cm–1: 3040, 2915, 1690, 1590,
1410, 1115–1100, 695. Н NMR spectrum, δ, ppm:
1
1.17 m (4Н, SiCH2), 1.63 m (4H, CH2), 2.33 s (6H,
CH3), 2.90 m (4H, CH2S), 7.36–7.48 m (10H, Ph). 13С
NMR spectrum, δС, ppm: 12.16 (SiCH2), 24.14 (CH2),
30.68 (CH3), 32.56 (CH2S), 127.98 (Cm), 129.46 (Cо),
134.84 (Cp), 135.19 (C1), 195.76 (C=O). 29Si NMR
spectrum, δSi, ppm: –6.96. Found, %: C 62.86; H 6.68;
S 14.20; Si 7.00. C22H28O2S2Si. Calculated, %: C
63.42; H 6.77; S 15.39; Si 6.73.
Bis[3-(allyldiphenylsilyl)propyl] sulfide (XVII).
1Н NMR spectrum, δ, ppm: 0.89 m (4Н, SiCH2), 1.65
m (4H, CH2), 2.12 d (4H, SiCH2Vi, J 7.9 Hz), 2.53 m
(4H, CH2S), 4.93 m (4H, =CH2), 5.81 d. d. t (2H, CH=,
J 8.5, 9.3, 17.2 Hz). 29Si NMR spectrum, δSi, ppm: –
15.03. Mass spectrum, m/z, (Irel, %, ion): 521 (56, [M –
C3H5]+), 223 (100, [Ph2SiCH2CH=CH2]+), 183 (29,
[223 – C3H4]+).
Allyldifluoro[3-(thioacetoxy)propyl]silane (XX).
Yield 30%, bp 90–95°С (6 mm Hg). 1Н NMR
spectrum, δ, ppm: 0.76 m (2Н, SiCH2), 1.62 m (2H,
CH2), 1.79 m (2H, SiCH2Vi), 2.31 s (3H, CH3), 2.86 t
(2H, CH2S, J 7.12 Hz), 5.02 d (1Н, =CHА, J 9.8 Hz),
5.05 d (1H, =CHВ, J 17.2 Hz), 5.71 d. d. t (1H, CH=, J
7.5, 9.7, 17.4 Hz). 13С NMR spectrum, δС, ppm: 11.04
t (SiCH2, J 15.11 Hz), 19.49 (SiCH2Vi), 22.34 (CH2),
30.50 (СН3), 31.66 (CH2S), 117.16 (=CH2), 128.85
(=CH), 195.85 (C=O). 19F NMR spectrum, δF, ppm:
Reaction of disubstituted diallylsilanes with
thioacetic acid. To 5.15 g of diallyldiphenylsilane in
10 ml of cyclohexane, 1.2 g of thioacetic acid in 2 ml
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SUSLOVA et al.
–139.61 quintet, (J ~302, 7.5 Hz). 29Si NMR spectrum,
δSi, ppm: –0.13 t (J ~302 Hz).
133.83 (=CH), 135.03 (Cо), 135.06 (C1). 29Si NMR
spectrum, δSi, ppm: –9.23. Found, %: C 72.27; H 7.27;
S10.34; Si 9.83. C18H22SSi. Calculated, %: C 72.48; H
7.38; S 10.73; Si 9.39.
Difluorobis[3-(thioacetoxy)propyl]silane (XXIII).
1
Yield 25%, bp 140–145°С (6 mm Hg). Н NMR
spectrum, δ, ppm: 0.85 m (4Н, SiCH2), 1.69 m (4H,
CH2), 2.31 s (6H, CH3), 2.86 t (4H, CH2S, J 6.98 Hz).
13С NMR spectrum, δС, ppm: 11.58 t (SiCH2, J 14.4
Hz), 21.77 (CH2), 30.50 (СН3), 31.39 (CH2S), 195.36
(C=O). 19F NMR spectrum, δF, ppm: –139.22 quintet
(J 304.2, 7.53 Hz).29Si NMR spectrum, δSi, ppm: –0.14
t (J 304.2 Hz).
The NMR spectra of compounds VIII and XI
coincide with those reported in [9, 12].
Allyldimethoxy(3-sulfanylpropyl)allylsilane (IX).
A mixture of 6.3 g of lallyl(3-chloropropyl)dimethoxy-
silane, 2.29 g of thiourea, and 0.063 g of tetrabutyl-
ammonium iodide in 5 ml of DMF was heated at 90°С
over the course of 20 h, decomposed with dry
ammonia for 1.5 h, diluted with 15 ml of pentane, and
argon was bubbled with stirring for 45 min. The
precipitate was extracted with methanol and filtered
off. After removal of the solvent and vacuum
distillation, 0.78 g (13%) of thiol IX was obtained, bp
83–85°С (10 mm Hg), nD20 1.4633. IR spectrum, ν, cm–1:
2915, 2560, 1630, 1395, 1055, 800.
Allyldimethoxy[3-(thioacetoxy)propyl]silane (XXI).
1
Yield 40%, bp 155–160°С (6 mm Hg), nD19 1.4720. Н
NMR spectrum, δ, ppm: 0.68 m (2Н, SiCH2), 1.57 m
(2H, CH2), 1.61 d (2H, SiCH2Vi, J 7.7 Hz), 2.26 s (3H,
CH3), 2.82 t (2H, CH2S, J 7.1 Hz), 3.48 s (6Н, МеО),
4.89 d (1H, =CHА, J 10.0 Hz), 4.92 d (1H, =CHВ, J
17.0 Hz), 5.74 d. d. t (1H, CH=, J 8.2, 10.0, 17.0 Hz).
13С NMR spectrum, δС, ppm: 11.13 (SiCH2), 19.74
(SiCH2Vi), 23.03 (CH2), 30.53 (СН3), 32.08 (CH2S),
50.46 (СН3О), 114.71 (=CH2), 132.58 (=CH), 195.55
(C=O). 29Si NMR spectrum, δSi, ppm: –9.7.
Photochemical cyclization of thiols was
performed as described in [12].
Reaction of dimethyldiallylsilane with complex
BF3·2AcOH. To 0.815 g of diallyldimethylsilane in
50 ml of СН2Сl2, a solution of 1.09 g of BF3·2AcOH in
20 ml of СН2Сl2 was added dropwise over the course
of 1.5 h under argon at room temperature; the
temperature increased to 32°С. The evolved gaseous
products were trapped in a bubbler with CCl4, cooled
to –20°С. After completion, the reaction mixture was
stirred for 30 min at room temperature and refluxed
until gas evolution ceased (~30 min). The solution of
the evolved gaseous products in ССl4, contained a
mixture of difluorodimethyl-silane and propene (NMR
data, internal reference cyclohexane).
Dimethoxybis[3-(thioacetoxy)propyl]dimethoxy-
silane (XXIV). Yield 23%, bp 215–220°С (6 mm Hg),
1
nD19 1.4961. Н NMR spectrum, δ, ppm: 0.63 m (4Н,
SiCH2), 1.57 m (4H, CH2), 2.25 s (3H, CH3), 2.81 t
(4H, CH2S, J 7.5 Hz), 3.44 s (6Н, МеО). 13С NMR
spectrum, δС, ppm: 11.39 (SiCH2), 23.15 (CH2), 30.57
(СН3), 32.09 (CH2S), 50.30 (МеО), 195.42 (C=O). 29Si
NMR spectrum, δSi, ppm: –5.49.
Allyldiphenyl(3-sulfanylpropyl)silane (Х). To a
solution of sodium hydride in 13 ml of ethanol (рН 9–
10), 2 g of allyldiphenyl[3-(thioacetoxy)propyl]silane
in 11 ml of ethanol was added dropwise over the
course of 1 h under argon, and the mixture was
refluxed for 6 h. After filtration and removal of the
solvent in the presence of the (4-tert-butylcatechol)
inhibitor, 1.08 g (62%) of thiol Х was isolated by
vacuum distillation, bp 160–165°С (1 mm Hg). An
analytically pure sample was obtained by column
chromatography on silica, eluent hexane–ether, 80:1–
15:1. Rf 0.61. IR spectrum, ν, cm–1: 3060, 2905, 2560,
1
Difluorodimethylsilane (XXVII). Н NMR spec-
trum, δ, ppm: 0.27 t (CH3, J 1.2 Hz). 19F, δF, ppm:
–129.79 septet (1JSiF 290.7, 3JНF 6.1 Hz).
1
Propene (XXVIII). Н NMR spectrum, δ, ppm:
1.66 d (3Н, CH3, J 6.4 Hz), 4.83 d (1Н, =СНcis, J
10.1 Hz), 4.91 d (1Н, =СНtrans, J 17.0 Hz), 5.69 d.d.q
(1Н, СН=, J 17.0, 10.1, 6.4 Hz). 13С NMR spectrum,
δС, ppm: 18.81 (CH3), 115.39 (=CH2), 132.48 (CH=).
1
1620, 1580, 1405, 1095, 680. Н NMR spectrum, δ,
ppm: 1.23 m (2Н, SiCH2), 1.33 t (1Н, SH, J 8.1 Hz),
1.72 m (2H, CH2), 2.14 d (2H, SiCH2Vi, J 7.9), 2.55 m
(2H, CH2S), 4.92 m (2H, =CH2), 5.80 m (1H, CH=),
7.39–7.52 m (10H, Ph). 13С NMR spectrum, δС, ppm:
11.45 (SiCH2), 20.52 (SiCH2Vi), 28.20 (CH2), 28.46
(CH2S), 114.61 (=CH2), 127.83 (Cm), 129.49 (Cp),
ACKNOWLEDGMENTS
The authors are grateful to Yu.A. Chuvashev for
taking the mass spectra and S.V. Kirpichenko (Irkutsk
Institute of Chemistry) for helpful discussion of the
results.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 9 2008

Si-DISUBSTITUTED DIALLYLSILANES IN HOMOLYTIC THIYLATION
1681
11. Kirhichenko, S.V., Tolstikova, L.L., Suslova, E.N.,
Albanov, A.I., and Voronkov, M.G., Phosphorus, Sulfur
Silicon, 1995, vol. 106, no. 1, p. 47.
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