Bromination of alkenes and alkynes with (bromodimethyl)sulfonium bromide

Article abstract of DOI:10.3184/030823408X314455

Alkenes and alkynes were brominated efficiently in high yields with (bromodimethyl)sulfonium bromide in acetonitrile at room temperature. Alkenes produced the corresponding trans-dibromo compounds while alkynes (except phenylacetylene) afforded both the trans-dibromo products (major) and the tetrabromo derivatives (minor). However, phenylacetylene furnished solely the tetrabromo compound.

Full text of DOI:10.3184/030823408X314455

188 RESEARCH PAPER
APRIL, 188–190
JOURNAL OF CHEMICAL RESEARCH 2008
Bromination of alkenes and alkynes with (bromodimethyl)sulfonium
bromide
Biswanath Das*, Yallamalla Srinivas, Chittaluri Sudhakar and Bommena Ravikanth
Organic Chemistry Division-I, Indian Institute of Chemical Technology, Hyderabad-500 007, India
Alkenes and alkynes were brominated efficiently in high yields with (bromodimethyl)sulfonium bromide in
acetonitrile at room temperature. Alkenes produced the corresponding trans-dibromo compounds while alkynes
(except phenylacetylene) afforded both the trans-dibromo products (major) and the tetrabromo derivatives (minor).
However, phenylacetylene furnished solely the tetrabromo compound.
Keywords: alkene, alkyne, (bromodimethyl)sulfonium bromide
O
Br
The conversion of alkenes and alkynes into their
corresponding bromo derivatives is useful in organic synthesis
as the bromine can be transformed to various other functional
groups.1 Brominated alkenes are also used for the preparation
of organometallic reagents.2 The bromination of alkenes and
alkynes can be accomplished by using hazardous elemental
bromine.1 Some alternative methods for bromination which
do not employ bromine directly have also been developed.1,3-9
However, the cost of the reagents, harsh reaction conditions
and unsatisfactory yields due to side reactions, are
disadvantages of many of these methods.
(Me2S+Br) Br-
MeCN, r.t.
O
Br
25 min
Cl
Cl
96 %
Br
Br
(Me2S+Br) Br-
MeCN, r.t.
Br
H
Br
30 min
94 %
Scheme 1
In connection with our work10,11 on the application of
(bromodimethyl)sulfonium bromide12-15 in the development
of useful synthetic methodologies we have discovered that
this reagent is highly effective for bromination of both alkenes
and alkynes (Scheme 1).
A series of alkenes and alkynes were brominated at room
temperature in short reaction times (15–30 min) following
the above method (Table 1). The products were formed in
excellent yields. All the alkenes produced the corresponding
vicinal trans-dibromo compounds. However, the alkynes
(except phenylacetylene) produced both the dibromo (trans)
and tetrabromo compounds. The dibromo compounds
were the major products. Phenylacetylene formed only the
tetrabromo product in a yield of 94%. The structures of the
bromo compounds were established from their spectral (1H
NMR and MS) data.
efficiently for solely bromination of alkenes and alkynes.
The plausible mechanism of the reaction is shown below
(Scheme 2).
In conclusion,
a
useful application of (bromo-
dimethyl)sulfonium bromide as an efficient reagent for the
bromination of alkenes and alkynes in short reaction times
and in excellent yields under mild reaction conditions has
been discovered.
Experimental
Melting points were measured on a Büchi 510 instrument and
are uncorrected. The spectra were determined with the following
instruments: NMR, Varian Gemini 200 MHz and MS: FABMS VG
Autospec, Column chromatography was performed over silica gel
(BDH, 100-200 mesh) and TLC with silica gel GF254
.
(Bromodimethyl)sulfonium bromide12-15 is an inexpensive
reagent. Its application has not yet been fully explored.
Previously one protocol for the treatment of alkenes with
(bromodimethyl)sulfonium bromide at 0oC afforded mainly
the corresponding 1-bromo-2-sulfonium bromides along
with 1,2-dibromides.14 Here the reagent has been employed
General experimental procedure
An alkene (0.5 mmol) or alkyne (0.5 mmol) and (bromo-
dimethyl)sulfonium bromide (0.6 mmol) were added to acetonitrile
(5 ml). The mixture was stirred at room temperature and the reaction
was monitored by TLC. After completion, the solvent was evaporated
..
R
+
H
Br
Br
H
+
R
(Me2SBr )Br
R
H
R1
Me2S
Br
+
+
R1
H
H
R1
H
S
Me
Me
Br
Br
Br
H
R
R1
H
Br
Scheme 2
* Correspondent. E-mail: biswanathdas@yahoo.com
PAPER: 08/5092

JOURNAL OF CHEMICAL RESEARCH 2008 189
Table 1 Preparation of dibromo compounds from alkenes and alkynes using (bromodimethyl) sulfonium bromide
Entry
Substrate
Producta
Time/min
Isolated yield/%
M.p. (m.p.)Lit/°C
Br
1
15
96
74
Br
(74–76)8
Br
2
3
4
15
15
15
94
98
93
56–58
Viscous
Viscous
Br
Br
Br
Br
Br
H3C
H3C
Br
O
O
Br
Cl
Cl
Ph
Ph
Ph
Br
5
6
7
15
25
25
95
92
94
233–234
(235)5
H
H
Br
Ph
Br
O
O
Ph
Ph
154–155
(156–158)8
Ph
Ph
Br
O
Br
O
CH3
CH3
Viscous
Meo
Br
MeO
O
Br
O
8
9
25
15
96
95
160–161
Cl
Br
Cl
Br
Br
Colourless oil
Br
CH2
(CH2)5 CH
(CH2)11 CH
CH3
10
11
15
15
92
Viscous liquid
Viscous
CH2
Br
(CH2)5 CH
CH3
Br
CH2
CH3
CH2
Br
(CH2)11
91
94
CH3
CH
Br
Br
H
Br
Br
12
13
30
30
74
(72)6
(CH2)3
CH3
Br
61
29
Pale yellow oil
Viscous
C
C
Br
H
(CH2)3 CH CH
CH3
+
Br
Br
C
H
C
(CH2)3
CH3
Br Br
aThe structures of the products were determined from spectral (1H NMR and MS) data.
The spectra (1H NMR and MS) of the unknown bromo compounds
are given below.
Compound(2):Whitesolid.M.p.56–58°C.1HNMR(CDCl3,200MHz):
d 7.55 (d, J = 8.0 Hz, 2H), 7.35 (d, J = 8.0 Hz, 2H), 5.05 (dd,
under vacuum and water (10 ml) was added. The mixture was extracted
with EtOAc (3 ¥ 10 ml) and the extract was dried and concentrated.
The crude mass was subjected to column chromatography (silica gel,
hexane-EtOAc) to offord the pure dibromo or tetrabromo product.
PAPER: 08/5092

190 JOURNAL OF CHEMICAL RESEARCH 2008
J = 9.0, 5.0 Hz, 1H), 4.04 (dd, J = 12.0, 5.0 Hz, 1H), 3.94 (dd,
J = 12.0, 9.0 Hz, 1H). FABMS: m/z 363, 365, 367, 369 [M + Na]+. Anal.
Calcd for C8H7Br3: C, 27.99; H, 2.04%. Found: C, 28.19; H, 2.02%.
Received 9 February 2008; accepted 18 April 2008
Paper 08/5092 doi: 10.3184/030823408X314455
1
Compound (4): Viscous oil. H NMR (CDCl3, 200 MHz): d 7.24
References
(d, J = 8.0 Hz, 2H), 6.85 (d, J = 8.0 Hz, 2H), 3.85 (d, J = 6.0 Hz,
2H), 4.45–4.26 (m, 3H). FABMS: m/z 349, 351, 353, 355 [M + Na]+.
Anal. Calcd for C9H9OBr2Cl: C, 32.88; H, 2.74%. Found: C, 33.12;
H, 2.81%.
1
L.F. Fieser and M. Fieser, Reagents for organic synthesis, Wiley,
New York, 1967, Vol.1, p. 967; H. O. House, Modern synthetic reactions,
2nd Ed., W.A. Benjamin Inc., 1972. p. 422.
Compound (7): Viscous. 1H NMR (CDCl3, 200 MHz): d 7.92 (d,
J = 8.0 Hz, 2H), 6.94 (d, J = 8.0 Hz, 2H), 3.91 (s, 2H), 3.86 (s, 3H),
2.56 (s, 3H). FABMS: m/z 357, 359, 361 [M + Na]+. Anal. Calcd for
C11H12O2Br2: C, 39.29; H, 3.57%. Found: C, 39.49; H, 3.57%.
Compound (8): White solid. M.p 160–161°C. 1H NMR (CDCl3,
200 MHz): d 8.06 (d, J = 8.0 Hz, 2H), 7.80–7.30 (m, 7H), 5.71 (d,
J = 9.0 Hz, 1H), 5.57 (d, J = 9.0 Hz, 1H). FABMS: m/z 423, 425, 427,
429 [M + Na]+. Anal. Calcd for C15H11OBr2Cl: C, 44.72; H, 2.73%.
Found: C, 44.97; H, 2.71%.
2
3
4
5
6
7
8
9
R.D. Rieke and M.S. Sell, In Handbook of Grignard reagents, Ed.
G.S. Silverman, P.E.M. Rakita, Dekker, New York, 1996, Chap. 26, p. 527.
W.C. Baird, Jr., J.H. Surridge and M. Buza, J. Org. Chem., 1971, 36,
3324.
J. Berthelot, Y. Benammar and C. Lange, Tetrahedron Lett., 1991, 38,
4135.
G. Hazra, M.D. Chordia, B.B. Bahule, V.S. Pore and S. Basu, J. Chem.
Soc., Perkin Trans I, 1994, 1667.
N.B. Barhate, A.S. Gaajare, R.D. Wakharkar and A.V. Bedekar,
Tetrahedron., 1999, 55, 11127.
R. Rodebaugh, J.S. Dahenham, B. Fraser-Reid and J.P. Snyder, J. Org.
Chem., 1999, 64, 1758.
V. Nair, S.B. Panicker, A. Augustine, T.G. George, S. Thomas and
M. Vairamani, Tetrahedron., 2001, 57, 7417.
T. Moriuchi, M. Yamaguchi, K. Kikushimia and T. Hirao, Tetrahedron
Lett., 2007, 48, 2667.
Compound (11): Viscous. 1H NMR (CDCl3, 200 MHz): d 4.13 (m,
1H), 3.84 (dd, J = 12.0, 4.0 Hz, 1H), 3.57 (dd, J = 12.0, 10.0 Hz,
1H), 2.15 (m, 1H), 1.76 (m, 1H), 1.64–1.20 (m, 20H), 0.88 (t,
J = 7.0 Hz, 3H). FABMS: m/z 377, 379, 381 [M + Na]+. Anal. Calcd
for C14H28Br2: C, 47.19; H, 7.87%. Found: C, 47.51; H, 7.88%.
Compound (13). Viscous. 1H NMR (200 MHz, CDCl3): d 4.16 (s,
1H), 2.65 (t, J = 7.0 Hz, 2H), 1.72–1.64 (m, 2H), 1.42-1.23 (m, 2H),
0.96 (t, J = 7.0 Hz, 3H). FABMS: m/z 421, 423, 425, 427, 429 [M
+ Na]+. Anal. Calcd for C6H10Br4: C, 17.91; H, 2.49%. Found: C,
18.14; H, 2.57%.
10 B. Das, Y. Srinivas, H. Holla, K. Laxminarayana and R. Narender,
Tetrahedron Lett., 2007, 48, 6681.
11 B. Das, H. Holla and Y. Srinivas, Tetrahedron Lett., 2007, 48, 61.
12 N. Furukawa, T. Inoue, T. Aida and S. Oue, Chem. Commun., 1973, 212.
13 G.A. Olah, D.V. Yashwant, A. Massoud and G.A. Suryaprakash, Synthesis,
1979, 720.
14 Y.L. Chow and B.H. Bakker, Synthesis, 1982, 648.
15 A.T. Khan, E. Mondal, S. Ghosh and S. Islam, Eur. J. Org. Chem., 2004,
2002.
The authors thank CSIR, New Delhi for financial assistance.
This paper is part 161 in the series “Studies on novel synthetic
methodologies”.
PAPER: 08/5092