Synthesis of acyclic α- and β-silyl sulfimides

Article abstract of DOI:10.1039/b004761i

Conversion of acyclic α- and β-silyl Sulfides by their treatment with sodium salts of N-chlorosulfonamides into the corresponding previously unknown sulfimides is described. The process is accompanied by a competing reaction resulting in the formation of α- or β-silyl sulfoxides. β-Silyl sulfamide (9b) undergoes thermolysis to generate trimethylvinylsilane. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/b004761i

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Synthesis of acyclic ꢀ- and ꢁ-silyl sulfimides
Elena N. Suslova, Svetlana V. Kirpichenko,* Aleksandr I. Albanov and Bagrat A. Shainyan
A. E. Favorskii Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of
Sciences, 1 Favorskii Str., RUS-664033 Irkutsk, Russia. E-mail: svk@irioch.irk.ru
1
Received (in Cambridge, UK) 14th June 2000, Accepted 18th July 2000
Published on the Web 1st September 2000
Conversion of acyclic α- and β-silyl sulfides by their treatment with sodium salts of N-chlorosulfonamides into the
corresponding previously unknown sulfimides is described. The process is accompanied by a competing reaction
resulting in the formation of α- or β-silyl sulfoxides. β-Silyl sulfimide (9b) undergoes thermolysis to generate
trimethylvinylsilane.
Recently we have described the preparation of the first acyclic
organosilicon sulfimide having the S᎐N moiety in the γ-position
᎐
to the silicon atom. However, attempts to obtain the corre-
sponding α-silyl sulfimide by the reaction of trimethylsilyl-
methyl ethyl sulfide with chloramine B in methanol led only to
the isolation of the silicon-free sulfimide.1
Now we report a detailed study of the reaction of α- and
β-organosilicon sulfides with chloramines as well as some
chemical properties of the new α- and β-silyl sulfimides.
Results and discussion
Treatment of trimethylsilylmethyl methyl sulfide 1 with chlor-
amine B in methanol results in its complete disappearance and
the formation of the expected α-silyl sulfimide 2a (Scheme 1).
Scheme 2
signals of the diastereotopic protons of the Si–CH2S units. One
set of peaks is associated with sulfimide 2a (see Experimental
section), while the singlet at δ 0.12 (Me3Si), doublets at δ 2.13
2
and 2.30 (diastereotopic protons of the SiCH2, JAB 13.6 Hz)
and the singlet at δ 2.50 (SMe) can be assigned to sulfoxide 5.
As in the case of dialkyl sulfides,3 the above reactions involve
the same intermediate chlorosulfonium ion A which is attacked
by either N- or O-nucleophiles to give α-silyl sulfimides 2a,b
or α-silyl sulfoxide 5, respectively. Thus, the ratio of 2a:5 was
estimated to be 3:1 from the peak areas of the corresponding
Me3Si and S–Me protons. In addition, arenesulfonamides 6a,b
are formed along with sulfoxide 5.
Scheme 1
1
Its structure was confirmed by comparison of the H NMR
spectrum of the reaction mixture with that of pure 2a obtained
as described below.
However, isolation of pure sulfimide 2a was greatly hindered
due to its solvolytic and hydrolytic lability. Thus, silica gel
column chromatography of the crude product after removal
of volatile components afforded sulfimide 4a in 75% yield. Tri-
methylmethoxysilane 3 was proved by 29Si NMR spectroscopy
to be the sole organosilicon compound present after the total
decomposition of sulfimide 2a.
To avoid the cleavage of the Si–C bond of 2a we used methyl-
ene chloride as a solvent in place of methanol. However, the
reaction occurred with a low conversion (25%) of sulfide 1
owing to the poor solubility of chloramines in this solvent.
Using benzyltriethylammonium chloride as a phase-transfer
catalyst2 facilitates the conversion of sulfide 1 which proceeds
via two competing reactions (Scheme 2).
α-Silyl alkyl sulfoxides were found to be thermally unstable
due to a facile sila-Pummerer rearrangement which can occur
even below room temperature.4,5 For this reason we failed to
isolate pure sulfoxide 5 and observed its conversion into the O-
trimethylsilyl hemithioacetal 7 when the reaction mixture was
1
allowed to stand at room temperature. H NMR monitoring
revealed that the signals relating to the sulfoxide 5 disappear,
while a singlet appears at δ 4.45 ppm which was assigned to the
Si–O–CH2–S unit in 7.6
We believe that the formation of sulfoxide 5 can be explained
by the presence of water of hydration or traces of moisture in
the system. Indeed, when sulfide 1 reacts with chloramine B
under water free conditions (in the presence of 4 Å molecular
sieves) sulfimide 2a is obtained as the sole product some
1
The H NMR spectrum of the crude reaction mixture con-
sists of two well-resolved sets of similar chemical shifts of
protons of the Me3Si and SMe groups as well as two pairs of
1
starting compound 1 being recovered. H NMR monitoring
3140
J. Chem. Soc., Perkin Trans. 1, 2000, 3140–3142
This journal is © The Royal Society of Chemistry 2000
DOI: 10.1039/b004761i

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showed that sulfimide 2a was relatively long-lived (ca. 4 days) in
CDCl3 solution under rigorous exclusion of air and moisture.
Due to decomposition and the loss of the product during the
work-up procedure, compound 2a was isolated analytically
pure only in low yield (about 10%).
Remarkably, the acyclic and cyclic six-membered α-silyl
sulfoxide and α-silyl sulfimide show very different stability: the
latter are solvolytically and thermally more stable than their
open-chain analogs.1,7
β-Silyl sulfide 8 also reacts readily with chloramine B (or T)
in methanol or methylene chloride to afford a mixture of β-silyl
sulfimide 9a and β-silyl sulfoxide 10 in a ~2:1 ratio, respectively
(Scheme 3).
in ppm are relative to tetramethylsilane as internal standard.
Mps were determined with a Boetius apparatus (VEB Analytik)
and are uncorrected. Thin layer chromatography was carried
out on silica gel plates (60 F-254) using UV light (254 nm) as
visualizing agent. Merck silica gel 60 (35–70 mesh) was used
for column chromatography. Solvents used were freshly distilled
from appropriate drying agents under an atmosphere of dry
argon prior to use: diethyl ether and tetrahydrofuran (THF)
(lithium aluminium hydride), methylene chloride, hexane and
ethyl acetate (calcium hydride). Methanol was distilled from
magnesium metal activated with iodine and stored over 4 Å
molecular sieves. All reactions were carried out in flame-dried
glassware under an argon atmosphere. Standard precautions to
avoid moisture were taken.
2-(Trimethylsilyl)ethyl methyl sulfide 8
Obtained by methylation of 2-(trimethylsilyl)ethanethiol with
methyl iodide in the presence of sodium hydride in THF by the
known procedure.11
Reaction of trimethylsilylmethyl methyl sulfide 1 with
chloramines
Scheme 3
(a) Chloramine B trihydrate (0.60 g, 2.24 mmol) in methanol
(6 ml) was added to a solution of sulfide 112 (0.30 g, 2.2 mmol)
in methanol (4 ml) at Ϫ5 ЊC. The resulting mixture was stirred
for 1 h at this temperature and then allowed to stand over-
night at room temperature. Volatile products were collected
under reduced pressure and distilled to give trimethylmethoxy-
silane 3 (0.12 g, 51%) contaminated with methanol. Compound
3 was identified by gas chromatography (10% Lukopren G-1000
on 45–60 mesh Chromaton N-AW-HMDS) by comparison
with an authentic sample and by its 29Si NMR spectrum
which is identical with that reported.13 Chromatography of the
remaining material on silica gel (hexane–ethyl acetate 9:1 to
0:1, MeOH) gave N-(phenylsulfonyl)-S,S-dimethylsulfimide 4a
(0.37 g, 75%) as white crystals, mp 129–130 ЊC,14 δH 2.64 (6H, s,
Me2S), 7.43 (3H, m, Hm,p), 7.83 (2H, d, Ho).
The compounds were separated by column chromatography
and appeared to be stable. In particular, they can be stored in
a refrigerator for several months without detectable decom-
position. Their structure was proved by the ABXXЈ spin system
shape of the CH2CH2 fragments.
It should be noted that a higher electron density at the sulfur
atom in α-silyl sulfides as compared with β-silyl sulfides8 favors
their transformations so that the reaction in Scheme 2 is much
more exothermic than the reaction outlined in Scheme 3. As
noted previously, the increasing ϩI-effect of the S-substituents
facilitates the imidation reaction of dialkyl sulfides.9
Like β-silyl sulfoxides,10 β-silyl sulfimides undergo thermal
decomposition to generate vinyl silanes (Scheme 4). Thus,
(b) To a stirred solution of sulfide 1 (0.21 g, 1.6 mmol)
and benzyltriethylammonium chloride (0.05 mol%, 0.02 g) in
methylene chloride (5 ml) was slowly added solid chloramine B
trihydrate (0.42 g, 1.6 mmol) in the presence of powdered 4 Å
molecular sieves (0.50 g) at Ϫ5 ЊC. When the addition of
chloramine was completed, the reaction mixture was stirred for
1 h at this temperature and was allowed to warm to room
temperature. The NaCl formed was filtered and the solvent
was removed on a rotary evaporator. The crude residue was
dissolved in ether, and after filtration to remove insoluble
material, the extract was concentrated under vacuum. This
procedure was repeated 2–3 times and the remaining white
solid was dried under high vacuum (1 mmHg) for 1–2 h to
afford N-(phenylsulfonyl)-S-methyl-S-(trimethylsilylmethyl)-
sulfimide 2a (0.045 g, isolated yield 10%), mp 30–32 ЊC (Found:
C, 45.02; H, 6.60; N, 4.72; S, 22.29; Si, 8.93. C11H19NS2SiO2
requires C, 45.67; H, 6.57; N, 4.84; S, 22.15; Si, 9.69%);
νmax/cmϪ1 3080, 1620 (Ph), 1280, 1130 (SO ), 940, 735 (S᎐N)
Scheme 4
heating of a DMSO solution of 9b in an NMR tube at 110 ЊC
for 10 min results in the appearance in the spectrum of a well-
defined ABC spin system in the olefinic region at 5.6–6.3 ppm,
as well as a new Me3Si group at 0.06 ppm, all chemical shifts
and couplings completely coinciding with those of an authentic
sample of trimethylvinylsilane 11 [δ 0.02 (Me3Si), 5.69 (HA),
5.93 (HB), 6.15 (HC), J 4.0, 14.6, 20.3 Hz]. The presence of
sulfonamide 6b was proved by comparison of the spectrum
of the thermolysis products with that of an authentic sample.
N-(Methylthio)sulfonamide 12 formed as an intermediate could
be detected by NMR (δNH 9.63 in DMSO-d6) but was not
isolated.
᎐
2
and 830 (Si–C); δH 0.20 (9H, s, Me3Si), 2.19 (1H, d, HA in
SiCH2), 2.42 (1H, d, HB in SiCH2, 2JAB 13.6), 2.55 (3H, s, SMe),
7.39 (3H, m, Hm,p), 7.75 (2H, d, Ho); δSi 0.235.
The work-up was accompanied by decomposition of com-
pound 2a to give sulfimide 4a (0.34 g, 53%), which was purified
as described above.
Experimental
IR spectra were recorded on
N-(p-Tolylsulfonyl)-S-methyl-S-(trimethylsilylmethyl)sulfimide
2b
a Specord-IR-29 spectro-
photometer in pellets with KBr. 1H, 13C, and 29Si NMR spectra
were measured on a Bruker DPX spectrometer operating at
400 MHz for protons, 100 MHz for carbon and 80 MHz for
the silicon nucleus. J values are given in Hz. All spectra
were obtained for solutions in CDCl3, chemical shifts given
Prepared from sulfide 1 as above with chloramine B (procedure
b). Compound 2b (0.04 g, 6%) was obtained as a white solid,
mp 66–67 ЊC (Found: C, 46.89; H, 7.11; N, 4.63; S, 21.35;
Si, 8.88. C12H21NS2SiO2 requires C, 47.52; H, 6.93; N, 4.62; S,
J. Chem. Soc., Perkin Trans. 1, 2000, 3140–3142
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21.12; Si, 9.24%); νmax/cmϪ1 3040, 1600 (Ar), 1280, 1130 (SO2),
19.51; Si 17.09%); νmax/cmϪ1 1250 (Me3Si), 1030 (S=O), 870,
840 (C-S); δH 0.08 (9H, s, Me3Si), 0.81, 0.95 (2H, m, SiCH2,
AB-part of the ABXXЈ spin system, JAB 18.01, JXXЈ 5.04,
3JAX = 3JBXЈ = 3JAXЈ = 3JBX = 9.13), 2.54 (3H, s, SMe), 2.65
(2H, m, SCH2, XXЈ-part of the ABXXЈ spin system); δC Ϫ1.91
(Me3Si), 8.61 (SiCH2), 37.36 (SMe), 49.83 (SCH2); δSi 2.97.
940, 730 (S᎐N), 840 (Si–C) and 805 (Ar); δ 0.20 (9H, s, Me Si),
᎐
H
3
2.18 (1H, d, HA in SiCH2), 2.40 (1H, d, HB in SiCH2, 2JAB 13.5),
2.42 (3H, s, CMe), 2.62 (3H, s, SMe), 7.28 (2H, d, Hm), 7.79
(2H, d, Ho, 3J 8.4). δSi Ϫ0.506.
2
2
In addition, N-(p-tolylsulfonyl)-S,S-dimethylsulfimide (4b)
was obtained as a decomposition product in 65% yield, mp
157–159 ЊC.14
Acknowledgements
Reactions of 2-(trimethylsilyl)ethyl methyl sulfide 8 with
chloramines
We are grateful to Professor V. A. Pestunivich for helpful
discussions.
Chloramine B trihydrate (0.80 g, 2.97 mmol) was added to a
solution of compound 8 (0.44 g, 2.97 mmol) and benzyltriethyl-
ammonium chloride (0.05 mol%, 0.03 g) in 10.5 ml methylene
chloride at Ϫ5 ЊC and the mixture was stirred for 2 h at this
temperature. The solvent was removed under reduced pressure
and the residue chromatographed on silica gel with a system of
increasing polarity (hexane–ethyl acetate 9:1 to 0:1, MeOH).
Two fractions were isolated, one containing N-(phenylsulf-
onyl)-S-methyl-S-[2-(trimethylsilyl)ethyl]sulfimide 9a (0.53 g,
59%), and the other containing methyl 2-(trimethylsilyl)ethyl
sulfoxide 10 (0.18 g, 36%).
References
1 S. V. Kirpichenko, E. N. Suslova, A. I. Albanov and B. A. Shainyan,
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and B. A. Shainyan, Zh. Obshch. Khim., 1997, 67, 1542; S. V.
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445, 29.
A similar procedure with chloramine T gave N-(p-tolyl-
sulfonyl)-S-methyl-S-[2-(trimethylsilyl)ethyl]sulfimide 9b (0.33
g, 65%), and compound 10 (0.10 g, 33%).
Compound 9a: Rf (ethyl acetate) 0.5. White crystals, mp
63–65 ЊC (Found: C, 46.89; H, 6.20; N, 4.34; S, 21.24; Si, 9.05.
C12H21NS2SiO2 requires C, 47.52; H, 6.93; N, 4.62; S, 21.12; Si,
9.24%); νmax/cmϪ1 3070, 1630 (Ph), 1290, 1130 (SO2), 970, 740
(S᎐N); δ 0.006 (9H, s, Me3Si), 0.64, 0.84 (2H, m, SiCH2, AB-
᎐
H
2
3
part of the ABXXЈ spin system, JAB 13.6, JAX = 3JBXЈ = 4.2,
3JAXЈ = 3JBX = 14.1), 2.53 (3H, s, SMe), 2.82 (2H, m, CH2S, XXЈ-
part of the ABXXЈ spin system, JXXЈ 1.5), 7.45 (3H, m, Hm,p),
2
7.90 (2H, d, Ho); δC Ϫ2.07 (Me3Si), 9.62 (SiCH2), 32.98 (SMe),
47.23 (SCH2), 126.73 (Cm), 128.56 (Co), 131.14 (Cp), 144.47 (Ci);
δSi 2.95.
9 F. Ruff, K. Komoto, N. Furukawa and S. Oae, Tetrahedron, 1976,
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E. Fujita, J. Chem. Soc., Chem. Commun., 1982, 281.
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13 H. Marsmann, in NMR: Basic Principles and Progress, eds.
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Compound 9b: Rf (ethyl acetate) 0.5. White crystals, mp 93–
95 ЊC (Found: C, 49.28; H, 7.29; N, 4.45; S, 20.78; Si, 8.38.
C13H23NS2SiO2 requires C, 49.21; H, 7.26; N, 4.42; S, 20.19;
Si, 8.83%); νmax/cmϪ1 3020, 1600 (Ph), 1290, 1130 (SO2), 970,
750 (S᎐N) and 805 (Ar); δH 0.006 (9H, s, Me3Si), 0.67 and 0.85
᎐
(2H, m, SiCH2, AB-part of the ABXXЈ spin system, 2JAB 21.32,
3
3
3JXXЈ 4.49, JAXЈ = 3JBX = 15.99, JAX = 3JBXЈ = 6.33), 2.38 (3H,
s, CMe), 2.56 (3H, s, SMe), 2.81 (2H, m, CH2S, XXЈ-part
of the ABXXЈ spin system), 7.22 (2H, d, 3J 8.06, Hm), 7.78 (2H,
d, Ho).
Compound 10: Rf 0.80. Yellow oil (Found: C, 43.60; H,
9.75; S, 19.88; Si 16.89. C6H16SSiO requires C, 43.85; H, 9.81; S,
14 M. V. Likhosherstov, Zh. Obshch. Khim., 1947, 17, 1477 (Chem.
Abstr., 1949, 43, 172e).
3142
J. Chem. Soc., Perkin Trans. 1, 2000, 3140–3142