Convenient method for the preparation of aryl sulfinyl chlorides

Article abstract of DOI:10.1055/s-2001-17437

Reaction of activated arenes with thionyl chloride in the presence of montmorillonite K-10 clay affords the corresponding aryl sulfinyl chlorides in good yield.

Full text of DOI:10.1055/s-2001-17437

LETTER
1573
Convenient Method for the Preparation of Aryl Sulfinyl Chlorides
Preparation of
A
ry
.
l
S
ulfinyl
Ch
N
lorides . Karade,* S. S. Kate, R. N. Adude
School of Chemical Sciences, S. R. T. M. University, Nanded-431 606, India
Fax +0091(2462)29245; E-mail: vainan@rediffmail.com
Received 16 July 2001
time (entry 1j). It is noteworthy that sulfinyl chlorides are
obtained in virtually pure states as no by products are
formed in the reaction.
Abstract: Reaction of activated arenes with thionyl chloride in the
presence of montmorillonite K-10 clay affords the corresponding
aryl sulfinyl chlorides in good yield.
Key words: sulfinylation, thionyl chloride, montmorillonite K-10
clay
Table Montmorillonite K-10 Clay Mediated Sulfinylation of Are-
nes.a
Adduct Arene (1)
Time
(h)
Product (2)
Yieldb,c
(%)
Sulfinyl chlorides constitute the most valuable and versa-
tile intermediates for the preparation of chiral sulfoxides,
sulfinates and other natural products containing sulfur at-
om.1 Despite their synthetic utility, the most practical
methods available for their preparation include (1) reac-
tion of sulfinic acid with thionyl chloride,2a (2) treatment
of thiol ester with thionyl chloride2b and (3) reaction of
disulfides with chlorine.2c,d Although all of these methods
afford the sulfinyl chlorides in good yields, they suffer
from drawbacks such as use of hazardous reagent, over
oxidation and incompatibility with other functional
groups present. As only few sulfinic acids are commer-
cially available, we looked for an alternative and simple
procedure for direct sulfinylation of arenes. Direct prepa-
ration of arene sulfinyl chlorides from arenes remains lit-
tle explored. We rationlised that reaction of thionyl
chloride with arenes in the presence of trifluoro acetic
acid3 to furnish the corresponding sulfoxide can be ex-
ploited to our advantage to provide the corresponding
sulfinyl chlorides by judicious choice of the Lewis acid.
Accordingly, arenes were treated with thionyl chloride in
the presence of montmorillonite K-10 clay and as envis-
aged the reaction proceeds very smoothly to afford the re-
spective sulfinyl chlorides (Scheme) in high yield.
a
6
4
61
82
b
c
2
3
84
68
d
e
f
6
2
72
91
87
76
89
-
g
h
i
2
2
2
Scheme
j
14
No reaction
As is obvious from the Table our process provides good
yields of various substituted sulfinyl chlorides. However,
unactivated arenes suffered in terms of yield and reaction
a All the reactions were carried out in chloroform.
b Yields are of isolated products.
c All the products were identified by comparison of the physical and
spectral data with those of literature.
Synlett 2001, No. 10, 28 09 2001. Article Identifier:
1437-210X,E;2001,0,10,1573,1574,ftx,en;D09301st.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0936-5214

1574
N. N. Karade et al.
LETTER
In conclusion, the present method proceeds under mild
conditions using inexpensive thionyl chloride and eco-
friendly montmorillonite K-10 clay.4 Further, the simplic-
ity of the method coupled with use of easily available re-
agents should make it a method of choice for synthesizing
various substituted aryl sulfinyl chlorides.
Acknowledgement
We wish to thank UGC for support of this work.
References and Notes
(1) (a) Repichet, C.; Rouse, L.; Hernandet, P.; Dubac, J. J. Org.
Chem. 1999, 64, 6479. (b) Block, E. Angew. Chem., Int. Ed.
Engl. 1992, 31, 1135. (c) Holland, H. L. Chem. Rev. 1988,
88, 473. (d) Olah, G. A.; Gupta, B.; Narang, S. C. Synthesis
1977, 533.
(2) (a) Youn, J. H.; Herrmann, R. Syn. Commun. 1987, 72.
(b) Douglass, I. W.; Norton, R. V. J. Org. Chem. 1968,
2104. (c) Douglass, I. W.; Poole, D. R. J. Org. Chem. 1957,
536. (d) Joo-Hack, Y.; Rudolf, H. Tetrahedron Lett. 1986,
27, 1493.
Sulfinyl Chlorides 2f; Gerneral Procedure
To a well stirred solution of arene 1f (9 mmol) and montmorillonite
K-10 clay (1 g) in chloroform (10 mL) was introduced thionyl chlo-
ride (18 mmol) drop wise over a period of five minutes. After the
gas evolution ceased, the reaction mixture was warmed to 50 °C and
the progress of reaction was monitored by TLC. After completion
of the reaction, the clay was filtered off and solvent was removed
under vacuo to furnish the sulfinyl chloride 2f (1.5 g, 91%).
(3) Olah, G. A.; Marinet, E. R.; Prakash, G. K. S. Synlett. 1999,
1397.
(4) (a) Mckillop, A.; Young, D. W. Synthesis 1979, 401.
(b) Laszlo, P. Acc. Chem. Res. 1986, 19, 121. (c) Baltark, I.
M.; Aliyan, H. J. Chem. Res. 2000, 122.
Synlett 2001, No. 10, 1573–1574 ISSN 0936-5214 © Thieme Stuttgart · New York