LETTER
Anti-Markovnikov Addition of Thiols to Alkenes
791
was stirred at room temperature for the time given in
Table 2. The addition of thiols onto the carbon–carbon
double bond took place in five to nine hours, and provided
good to excellent yields of the desired product (78–97%,
Table 2). The versatility of this process was demonstrated
with respect to diverse cyclic and acyclic alkenes, and for
a wide range of aromatic and aliphatic thiols.
Table 2 Synthesis of Diorganyl Sulfides Catalyzed by Anhydrous
CeCl3
Entry Alkene 1
Product
Time Yield
(h) (%)a
S
1
5
9
96
81
It is important to point out that this route allowed the prep-
aration of tetrahydropyranyl thiol ethers in very good
yields using dihydropyran as substrate (entries 8–11,
Table 2). Regarding the regiochemistry, the only product
obtained during the course of this reaction was the anti-
Markovnikov product; this was determined by GC and 1H
NMR of the crude reaction mixture.
1a
3a
S
4
2
4
1b
3b
S
3
6
6
5
6
94
93
89
97
To conclude, we have developed a very simple, efficient
and green methodology for the synthesis of diorganyl sul-
fides in an anti-Markovnikov fashion through a new appli-
cation of cerium(III) as catalyst. The reactions occur
under solvent-free conditions at room temperature. The
significant advantages offered by this method are simple
operation, environmentally friendly experimental condi-
tions, high yields of isolated products and cost effective-
ness.
1c
3c
S
S
4
1d
3d
5
Cl
1d
3e
S
S
Acknowledgment
6
The authors thank FAPERGS, CAPES, and MCT/CNPq for finan-
cial support.
OMe
1d
3f
7
7
8
78
86
References and Notes
1d
(1) (a) Peach, M. E. Thiols as Nucleophiles, In The Chemistry of
the Thiol Group; Patai, S., Ed.; John Wiley & Sons: London,
1979, 721. (b) Organic Sulfur Chemistry; Oae, S., Ed.; CRC
Press: Boca Raton, 1991.
(2) Cremlyn, R. J. An Introduction to Organo-Sulfur Chemistry;
Wiley & Sons: New York, 1996.
(3) Curran, D. P. In Comprehensive Organic Synthesis, Vol. 4;
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646. (b) Screttas, C. G.; Micha-Screttas, M. J. Org. Chem.
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H. Chem. Lett. 1973, 355. (b) Belley, M.; Zamboni, R.
J. Org. Chem. 1989, 54, 1230. (c) Kanagasabapathy, S.;
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3g
3h
S
S
8
O
O
1e
9
7
81
O
O
O
O
Cl
1e
3i
S
S
10
8
9
88
83
O
OMe
1e
3j
11
O
1e
3k
a Isolated yield.
(8) Ranu, B. C.; Mandal, T. Synlett 2007, 925.
(9) Griesbaum, K. Angew. Chem., Int. Ed. Engl. 1970, 9, 273.
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(11) (a) Sabitha, G.; Yadav, J. S. In Encyclopedia of Reagents for
Organic Synthesis; Paquette, L. A., Ed.; Wiley-VCH:
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Giovannini, R.; Giuli, S.; Lanari, S.; Paoletti, M.;
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(12) (a) Silveira, C. C.; Mendes, S. R.; Libero, F. M.; Lenardão,
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