N-Hydroxyphthalimide catalyzed allylic oxidation of steroids with t-butyl hydroperoxide

Abstract

A new and optimized procedure for the allylic oxidation of Δ5-steroids with t-butyl hydroperoxide in the presence of catalytic amounts of N-hydroxyphthalimide (NHPI) under mild conditions was developed, showing excellent regioselectivity and chemoselectivity (functional group compatibility). It was found that Co(OAc)2 could enhance the catalytic ability of NHPI resulting in better yields and shorter reaction times. The reaction mechanism and the scope of the reaction with a variety of Δ5-steroidal substrates were also investigated.