Nucleophilic epoxidation of α-sulfonyl-α,β-unsaturated esters with m-CPBA

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Phosphorus, Sulfur, and Silicon
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Nucleophilic Epoxidation of
α-Sulfonyl-α,β-Unsaturated
Esters with m-CPBA
J. L. Garcća Ruano a , C. Fajardo a , A. Fraile a & M.
R. Martićn a
a Departamento de Qu'i mica Orgánica, Universidad
Autónoma de Madrid , Madrid, Spain
Published online: 16 Aug 2006.
To cite this article: J. L. Garcća Ruano , C. Fajardo , A. Fraile & M. R. Martićn
(2005) Nucleophilic Epoxidation of α-Sulfonyl-α,β-Unsaturated Esters with m-CPBA,
Phosphorus, Sulfur, and Silicon and the Related Elements, 180:5-6, 1489-1490, DOI:
10.1080/10426500590913302
To link to this article: http://dx.doi.org/10.1080/10426500590913302
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Phosphorus, Sulfur, and Silicon, 180:1489–1490, 2005
Copyright © Taylor & Francis Inc.
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500590913302
Nucleophilic Epoxidation of α-Sulfonyl-α,β-Unsaturated
Esters with m-CPBA
´
J. L. Garcıa Ruano
C. Fajardo
A. Fraile
M. R. Martın
´
Departamento de Qu´ımica Orga´nica, Universidad Auto´noma de Madrid,
Madrid, Spain
INTRODUCTION
m-CPBA is usually described as an electrophilic oxidant that transfers
oxygen to non electron-poor alkenes. There are a few reports about
the epoxidation with m-CPBA of deactivated olefins.1a−d The reactions
of 1-phenyl-(2-p-tolylsulfonyl)ethane1a,b and 2-nitro-1-phenylpropene1c
using m-CPBA in basic aqueous media were described. We report herein
the results obtained in the reaction of the title sulfones with m-CPBA.
RESULTS
The reactions of sulfinylfuranones 1a–c with an excess of m-CPBA in
CH2Cl2 at 0◦C for 1.5–8 h afforded the corresponding sulfones 2a–c,
which were not isolated and in situ evolved into the sulfonyl oxiranes
3a–c in good yields (75–89%). The reactions are stereoselective, afford-
ing only the products resulting from the anti approach of the reagent
with respect to the OEt group. Under similar conditions, furanone 4 did
not evolve into its epoxide derivative (Scheme 1).
SCHEME 1
Received July 9, 2004; accepted October 5, 2004.
Address correspondence to C. Fajardo, Departamento de Qu´ımica Orga´nica, Universi-
dad Auto´noma de Madrid, Cantoblanco, 28049 Madrid, Spain. E-mail: cristina.fajardo@
uam.es
1489

1490
J. L. Garc´ıa Ruano et al.
The above results suggest that m-CPBA is also able to act as a nu-
cleophile on the proper substrates, which lead us to investigate the
epoxidation of different α,β-unsaturated sulfones (5–6) with m-CPBA
(Scheme 2 and Table I).
SCHEME 2
TABLE I
Eq. m-CPBA/eq. base
T (◦C)
Time
Ratio 5:7
2.10/0
1.15/1.15 K2CO3
1.15/1.15 KOH
20
−20
−20
87 h
40 min
10 min
27:73
0:100 (91)
0:100 (88)
The reaction with m-CPBA in dichloromethane was complete to give
oxirane only in the case of the furanones 2. Cyclopentenone 5 afforded
only 73% of oxirane 7 after 87 h and the open-chain compounds did not
undergo epoxidation under these conditions. The addition of base to
solution of m-CPBA allowed us to obtain the sulfonyl-oxiranes 8 in good
yields; an increase in the reaction rate of 2 and 5 was also detected.
REFERENCE
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and M. Meneghin, Gazz. Chim. Ital., 108, 123 (1978); d) K. Ogura, S. Takahashi,
Y. Kawamoto, M. Suzuki, M. Fujita, Y. Suzuki, and Y. Sugiyama, Tetrahedron Lett.,
34, 2649–2652 (1993).