N-Hydroxyphthalimide catalyzed allylic oxidation of steroids with t-butyl hydroperoxide
Qian Zhao1, Chao Qian1, Xin-Zhi Chen1
1Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Zhejiang University, China; Department of Chemical and Biological Engineering, Zhejiang University, China.
Abstract:
A new and optimized procedure for the allylic oxidation of Δ(5)-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 Δ(5)-steroidal substrates were also investigated.
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