Nucleophilic epoxidation of alpha'-hydroxy vinyl sulfoxides.
The nucleophilic epoxidation of a variety of alpha'-(1-hydroxyalkyl) vinyl sulfones and sulfoxides has been studied. The sulfones give rise to anti oxiranes with modest (E) or excellent (Z) selectivities and in good yields. The (E)-sulfoxides display low reactivity within a reinforcing/nonreinforcing scenario. The use of t-BuOOLi in Et(2)O allows for a highly syn-selective epoxidation-oxidation. The (Z)-sulfoxides display a remarkably high reactivity under these conditions. The reinforcing (S,S(S)) diastereomers (3e-g) yield hydroxy sulfinyl oxiranes with high yields and selectivities. In contrast, the (R,S(S)) diastereomers (4e-g) show diminished reactivities and a very substrate-dependent stereochemical outcome. The structure of these oxiranes has been secured by chemical correlations and an X-ray crystal structure.
Fernández de la Pradilla
Roberto
R
Instituto de Química Orgánica, CSIC, Juan de la Cierva, 3, 28006 Madrid, Spain. iqofp19@iqog.csic.es
Fernández
Jorge
J
Manzano
Pilar
P
Méndez
Paloma
P
Priego
Julián
J
Tortosa
Mariola
M
Viso
Alma
A
Martínez-Ripoll
Martín
M
Rodríguez
Ana
A