Halo(trimethyl)silanes as activating coreagents in sulfenylation of olefins [1]

Full text of DOI:10.1007/s11172-006-0500-z

Russian Chemical Bulletin, International Edition, Vol. 55, No. 10, pp. 1865—1866, October, 2006
1865
Letters to the Editor
Halo(trimethyl)silanes as activating coreagents
in sulfenylation of olefins
N. V. Zyk, A. Yu. Gavrilova,ꢀ O. A. Mukhina, O. B. Bondarenko, and N. S. Zefirov
Department of Chemistry, M. V. Lomonosov Moscow State University,
1
Leninskie Gory, 119992 Moscow, Russian Federation.
Fax: +7 (495) 939 0290. Eꢀmail: gavrilova@org.chem.msu.ru
Sulfenylation reactions of alkenes have recently beꢀ
come of particular importance in both the theory and
practice of organic synthesis.1,2 Progress in this area is
them provide comprehensive information on the addition
stereochemistry, the effective electrophilicity, and the naꢀ
ture of the electrophilic species.
3
,4
largely due to the effective electrophilicity concept used
to develop various ways of activating weak electrophiles.
However, despite a great number of relevant investiꢀ
We found that the reactions occur under mild condiꢀ
tions (CH Cl as a solvent, 20 °C, 15—20 min). Ethyl
2
2
benzenesulfenate (1) in the presence of bromo(triꢀ
methyl)silane or chloro(trimethyl)silane added to norꢀ
bornene to give the corresponding βꢀhalogenated phenyl
sulfide 2 in high yields as the sole product (Scheme 1).
5
gations, it is still far from discovering a versatile reagent
that would allow rapid and easy access to βꢀhalogenated
aryl sulfides in high yields. The synthesis of βꢀbrominated
aryl sulfides is an especially pressing problem since the
degradation rates of the reagents are often higher than the
rate of addition.6
,7
Scheme 1
Sulfenic acid esters appear to be promising reagents.
8
Earlier, we have already demonstrated that sulfenic acid
esters activated with phosphorus oxohalides can react with
olefins. However, this method also has its inherent drawꢀ
backs, most substantial of which is separation of the target
products from products of reagent degradation, viz.,
phosphorus(V) acid esters.
Proceeding further in the study of addition of sulfenic
acid esters to olefins and in a search for new, more suitꢀ
able routes to βꢀhalogenated aryl sulfides, we investiꢀ
gated reactions of ethyl benzenesulfenate activated with
chloroꢀ and bromo(trimethyl)silanes with such olefins as
norbornene and cyclohexene. These compounds were
chosen as model substrates because the reactions with
X = Cl (a), Br (b)
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1798—1799, October, 2006.
066ꢀ5285/06/5510ꢀ1865 © 2006 Springer Science+Business Media, Inc.
1

1
866
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 10, October, 2006
Zyk et al.
The transꢀconfiguration of the product confirms the
3.36 (d, 1 H, CH—S, J = 4.3 Hz); 4.06 (d, 1 H, CH—Cl, J =
3
.1 Hz); 7.20—7.40 (m, 5 H, Ar).
electrophilic character of the reaction, while the absence
of the product of the Wagner—Meerwein rearrangement
suggests the low effective electrophilicity of the reagent.
The reaction of ethyl benzenesulfenate (1) activated
with halo(trimethyl)silanes with cyclohexene also gave
rise to only one product, namely, βꢀhalogenated phenyl
sulfide 3 in >90% yields.
transꢀ1ꢀBromoꢀ2ꢀphenylthiocyclohexane (3b) was obtained
from cyclohexene (0.2 g, 2.4 mmol) and ethyl benzenesulfenate
0.45 g, 2.9 mmol) activated with bromo(trimethyl)silane (0.44 g,
(
2
1
.9 mmol). The yield was 0.60 g (92%), Rf 0.73. H NMR
(
CDCl ), δ: 1.50 (m, 2 H, CH ); 1.73 (m, 3 H, CH of cycloꢀ
3
2
hexane); 1.92, 2.34, 2.47 (all m, 1 H each, CH of cyclohexane);
3.52 (d, 1 H, CH—S, J = 4.3 Hz); 4.30 (s, 1 H, CH—Cl);
7
.20—7.40 (m, 5 H, Ar).
1H NMR spectra were recorded on an Avance spectrometer
(
Bruker; 400 MHz) at 28 °C. Chemical shifts are given on the
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 05ꢀ03ꢀ32737)
and the Presidium of the Russian Academy of Sciences
Program "Theoretical and Experimental Study of the
Nature of Chemical Bonding and the Mechanisms of
Chemical Reactions and Processes").
δ scale with reference to HMDS as the internal standard. The
course of the reactions was monitored and the purity of the
products was checked by TLC on fixed silica gel (Silufol) with
light petroleum—ethyl acetate (3 : 1) as an eluent.
(
9
General procedure. A solution of ethyl benzenesulfenate (1)
(
~
2.5 mmol, 2 mL) in chloroform was added in a flow of argon at
20 °C to a vigorously stirred solution of an alkene (2.1 mmol)
in anhydrous chloroform. Then a solution of bromo(triꢀ
methyl)silane or chloro(trimethyl)silane (2.5 mmol) in chloroꢀ
form was slowly added dropwise. Stirring was continued until
the reaction was completed (15—20 min). The reaction mixture
was filtered through a column and the residue was concentrated
References
1
. N. V. Zyk, E. K. Beloglazkina, M. A. Belova, and N. S.
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and N. S. Zefirov, Izv. Akad. Nauk, Ser. Khim., 2002, 1356
in vacuo. The NMR spectra were identical with the literaꢀ
ture data.10
3
ꢀendoꢀChloroꢀ2ꢀexoꢀphenylthiobicyclo[2.2.1]heptane (2a)
[
Russ. Chem. Bull., Int. Ed., 2002, 51, 1468].
was obtained from norbornene (0.2 g, 2.1 mmol) and ethyl
benzenesulfenate (0.39 g, 2.5 mmol) activated with chloro(triꢀ
3
. N. S. Zefirov, V. A. Smit, I. V. Bodrikov, and M. Z. Krimer,
Dokl. Akad. Nauk SSSR, 1978, 240, 858 [Dokl. Chem., 1978
(Engl. Transl.)].
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. Yu. G. Gololobov and N. I. Gusar´, Sul´fenkhloridy [Sulfenyl
Chlorides], Nauka, Moscow, 1989, 175 pp. (in Russian).
. R. C. Fusson, C. C. Price, R. A. Bauman, O. H. Bullet,
W. R. Hatchard, and E. W. Maynert, J. Org. Chem., 1996,
methyl)silane (0.27 g, 2.5 mmol). The yield was 0.41 g (81%),
1
R 0.75. H NMR (CDCl ), δ: 1.36—1.57 (m, 2 H, H(5)endo
,
f
3
4
5
6
H(6)endo); 1.50 (d, 1 H, H(7)anti); 1.72 (m, 1 H, H(5)exo); 1.86
d, 1 H, H(7)syn, J = 10.5 Hz); 2.05 (m, 1 H, H(6)exo); 2.33 (br.s,
2
(
1
3
H, H(4)); 2.52 (br.s, 1 H, H(1)); 3.12 (t, 1 H, CH—S, J =
.2 Hz); 4.08 (d, 1 H, CH—Cl, J = 3.1 Hz); 7.20—7.40
(
m, 5 H, Ar).
ꢀendoꢀBromoꢀ3ꢀexoꢀphenylthiobicyclo[2.2.1]heptane (2b)
2
6
1, 469.
was obtained from norbornene (0.2 g, 2.1 mmol) and ethyl
benzenesulfenate (0.39 g, 2.5 mmol) activated with bromo(triꢀ
7
. N. Kharasch, C. M. Buess, and S. I. Strashun, J. Am. Chem.
Soc., 1952, 74, 3422.
8. N. V. Zyk, A. Yu. Gavrilova, O. A. Mukhina, O. B.
Bondarenko, and N. S. Zefirov, Zh. Org. Khim., 2006, 42,
No. 11 [Russ. J. Org. Chem., 2006, 42 (Engl. Transl.)].
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0. N. V. Zyk, E. K. Beloglazkina, S. E. Sosonyuk, M. N.
Bulanov, and Yu. B. Chudinov, Izv. Akad. Nauk, Ser. Khim.,
000, 1569 [Russ. Chem. Bull., Int. Ed., 2000, 49, 1557].
methyl)silane (0.38 g, 2.5 mmol). The yield was 0.59 g (92%),
1
R 0.73. H NMR (CDCl ), δ: 1.36—1.48 (m, 2 H, H(5)endo
,
f
3
H(7)anti); 1.58 (m, 1 H, H(6)endo); 1.72 (m, 1 H, H(5)exo); 1.85
d, 1 H, H(7)syn, J = 10.6 Hz); 2.04 (m, 1 H, H(6)exo); 2.30 (br.s,
(
9
1
3
H, H(4)); 2.53 (br.s, 1 H, H(1)); 3.22 (t, 1 H, CH—S, J =
.9 Hz); 4.11 (br.s, 1 H, CH—Cl); 7.20—7.40 (m, 5 H, Ar).
transꢀ1ꢀChloroꢀ2ꢀphenylthiocyclohexane (3a) was obtained
1
2
from cyclohexene (0.2 g, 2.4 mmol) and ethyl benzenesulfenate
0.45 g, 2.9 mmol) activated with chloro(trimethyl)silane (0.31 g,
.9 mmol). The yield was 0.53 g (98%), Rf 0.75. 1H NMR
CDCl ), δ: 1.44, 1.66, 1.80 (all m, 2 H each, CH of cycloꢀ
(
2
(
Received June 19, 2006;
3
hexane); 2.27, 2.39 (both m, 1 H each, CH of cyclohexane);
in revised form September 15, 2006