An efficient one-pot synthesis of vinyl sulphones via CAN mediated reaction of aryl sulphinates and alkenes

Article abstract of DOI:10.1016/S0040-4039(01)01377-6

Cerium(IV) ammonium nitrate mediated reaction of sodium arene sulphinate and sodium iodide with alkenes afforded vinyl sulphones in very good yields.

Full text of DOI:10.1016/S0040-4039(01)01377-6

TETRAHEDRON
LETTERS
Pergamon
Tetrahedron Letters 42 (2001) 6763–6765
An efficient one-pot synthesis of vinyl sulphones via CAN
†
mediated reaction of aryl sulphinates and alkenes
Vijay Nair,* Anu Augustine, Tesmol G. George and Latha G. Nair
Organic Chemistry Division, Regional Research Laboratory (CSIR), Trivandrum 695 019, India
Received 5 June 2001; revised 14 July 2001; accepted 26 July 2001
Abstract—Cerium(IV) ammonium nitrate mediated reaction of sodium arene sulphinate and sodium iodide with alkenes afforded
vinyl sulphones in very good yields. © 2001 Elsevier Science Ltd. All rights reserved.
Oxidative addition of soft anions to alkenes mediated
by cerium(IV) ammonium nitrate (CAN) has recently
been shown to offer a practical method for car-
Impressed by the efficiency of the reaction we extended
the studies to involve a number of aryl alkenes. The
reaction was found to be general and the results are
summarized in Table 1.
1–4
bonꢀheteroatom (CꢀN, CꢀS and CꢀBr) bond forma-
tion. In view of the success of these reactions and the
5
very efficient azidoiodination, it was anticipated that
In addition to styrenes the reaction appears to be
CAN mediated addition of sulphinate and iodine to
alkenes would lead to iodosulphones efficiently. In the
event, a facile reaction leading to the vinyl sulphone,
presumably via the expected iodosulphone, occurred. It
is noteworthy that the available methodology for vinyl
sulphone synthesis mainly consists of Horner–Emmons
reactions of carbonyl compounds and sulphonyl phos-
applicable to n-alkenes as illustrated in Scheme 2.
As a logical extension of this work, it was of interest to
study the oxidative addition of sulphinate and iodine to
alkynes. Phenylacetylene on reaction with p-toluene
sulphinate and sodium iodide in the presence of CAN
1
1
in acetonitrile afforded the iodo vinyl sulphone in
78% yield (Scheme 3).
6
7
phoranes, Peterson reactions and b-elimination of
8
9
selenosulphones or halosulphones. In view of the
1
0
importance of vinyl sulphones as versatile intermedi-
ates in organic synthesis and the known limitations of
existing methods, it was of interest to examine the
above reaction as a convenient alternative to the latter.
This reaction also appears to be general as attested by
the results presented in Table 2.
Mechanistically, the reaction may be considered to
proceed as follows. An oxygen centered radical gener-
ated by the oxidation of sulphinate with CAN resonates
With the stated objective, a mixture of styrene, p-tolu-
ene sulphinate and sodium iodide in acetonitrile was
treated with a solution of CAN. A facile reaction
occurred, and the vinyl sulphone 3 was formed in 82%
12
with a sulphonyl radical. This radical adds to styrene
to give a benzylic radical which is trapped by molecular
iodine produced by the fast combination of two iodine
radicals to give b-iodo vinyl sulphone. Spontaneous
1
3
yield (Scheme 1).
SO Na
SO2
2
i
+
+
NaI
1
Me
2
3 (82%)
i. CAN, dry CH CN, argon, rt, 45 min
Me
3
Scheme 1.
*
Corresponding author. Tel.: 91-471-490324; fax: 91-471-491712; e-mail: gvn@csrrltrd.ren.nic.in
Dedicated with best wishes to Professor Dr. Rolf Gleiter on the occasion of his 65th birthday.
†
0
040-4039/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4039(01)01377-6

6
764
V. Nair et al. / Tetrahedron Letters 42 (2001) 6763–6765
Table 1. Sulphinylation of styrenes
SO2
SO Na
2
i
+
R4
R1
R3
R1
R3
R4
R2
(a-i)
R2
4
4
2 R = Me,H
5 (a-i)
i. Nal, CAN, dry CH CN, argon, rt, 45 min
3
Entry
Substrate
R1
R2
R3
R4
Product
Yield (%)a
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4e
4f
4g
4h
4i
H
H
H
H
NO2
H
H
H
H
H
H
H
H
H
Me
H
Me
Me
H
Me
H
5a
5b
5c
5d
5e
5f
5g
5h
5i
76
83
80
80
88
85
72
76
70
Me
Me
H
Cl
Cl
OAc
1-Naphthyl
1-Naphthyl
H
H
Me
a
Isolated yield.
SO Na
CAN
2
I
i
SO R2
I
(
)5
+
+ NaI
2
(
)5
R1
I
I2
6
2
7
O
S
O
i. CAN, dry CH CN, argon, rt, 45 min
Ce(IV)
Ce(III)
3
O
S O
1
2
R = Me 2a
2b
R = phenyl 7a ( 65%)
1
R = H
2
7b ( 55%)
R = tolyl
O
S
O
O
S
Scheme 2.
O
I
I
SO2
SO Na
SO2
- HI
SO2
2
I2
H
+
I
i
+
+
NaI
O2S
8
2
9
(78%)
Me
Me
i. CAN, dry CH CN, argon, rt, 45 min
3
Scheme 3.
Scheme 4.
Table 2. Iodo-sulphinylation of acetylenes
SO Na
I
2
H
i
+
+ NaI
R1
O S
2
R2
R2
R3
R1
R3
1
0 (a-d)
11 (a-d)
i. CAN, dry CH CN, argon, rt, 45 min
3
Entry
Substrate
R1
R2
R3
Product
Yield (%)a
1
2
3
4
10a
10b
10c
10d
H
H
OMe
NO2
Me
OMe
H
H
Me
H
11a
11b
11c
11d
79
75
65
65
H
Me
a
Isolated yield.

V. Nair et al. / Tetrahedron Letters 42 (2001) 6763–6765
6765
elimination of a molecule of hydrogen iodide from this
iodo sulphone would then afford the corresponding
vinyl sulphone (Scheme 4).
10. (a) Fuchs, P. L.; Braish, T. F. Chem. Rev. 1986, 86, 903;
(b) De Lucci, O.; Pasquato, L. Tetrahedron 1988, 44,
6755.
11. Truce, W. E.; Wolf, G. C. J. Am. Chem. Soc. 1971, 36,
In conclusion, we have devised a novel and very
efficient synthesis of vinyl sulphones. The experimental
simplicity and mild reaction conditions make the
present one-pot reaction attractive over the other avail-
able methods.
1727.
12. (a) Narasaka, K.; Mochizuki, T.; Hayakawa, S. Chem.
Lett. 1994, 1705; (b) Mochizuki, T.; Hayakawa, S.;
Narasaka, K. Bull. Chem. Soc. Jpn. 1996, 69, 2317.
13. All new compounds were fully characterised.
Typical experimental procedure and selected data for 3:
A mixture of styrene (104 mg, 1 mmol), p-toluene sulphi-
nate (178 mg, 1.5 mmol) and sodium iodide (224 mg, 1.5
mmol) was taken in dry acetonitrile (12 mL) in a two
necked round-bottomed flask fitted with a pressure equal-
ising funnel containing CAN (1.260 g, 2.3 mmol) dis-
solved in dry acetonitrile (8 mL). Both the solutions were
simultaneously bubbled with argon, which was deoxy-
genated by passing through Fieser’s solution for 15 min.
Then the CAN solution was added dropwise at room
temperature and the reaction mixture was stirred vigor-
ously under an argon atmosphere for 45 min. When the
reaction was completed, the solvent was removed in
vacuo, the reaction mixture was diluted with water (100
mL) and extracted using dichloromethane (4×25 mL).
The combined organic extracts were washed with water,
then with saturated sodium thiosulphate solution, fol-
lowed by saturated brine, and finally dried over anhy-
drous sodium sulphate and concentrated in vacuo.
Column chromatography on neutral alumina using hex-
ane–ethyl acetate (80:20) afforded the vinyl sulphone (211
mg, 82%) as a colourless crystalline solid, which was
recrystallised from dichloromethane–hexane mixture, mp
119–121°C. IR (KBr) wmax: 3046, 2915, 1613, 1594, 1447,
Acknowledgements
A.A., T.G.G. and L.G.N. thank the CSIR, New Delhi,
for research fellowships. The authors also thank Ms.
Soumini Mathew for high-resolution NMR spectra and
Mrs. S. Viji for elemental analysis.
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