A Mild and Efficient Procedure for Asymmetric Michael Additions of α-Bromochalcone with Cyclohexanone Catalyzed by Different Bases

摘要

A mild and efficient procedure for Michael addition of α-bromochalcone with cyclohexanone has been developed. In the presence of sodium ethoxide, α-bromochalcone reacted with cyclohexanone to afford Michael products in moderate to high yield and good diastereoselectjvities. Especially, while CH3CH2ONa or t-BuOK as catalyst, the unexpected products were obtained, which were the compound 4a((8aR,9S)-4a,8a-dihydroxy- 10-phenyl-tetradecahydro-phenanthren-9-yl)(phenyl)methanone) and 4b(((8aR,9R)-4a,9-dihydroxy-10-phenyl-tetradecahydrophenanthren-9-yl)(phenyl)methanone).