Synthetic studies of withanolides. Part I. Synthesis of 5,6β-epoxy-4β-hydroxy-5β-cholest-2-en-1-one and related compounds

Abstract

The title compounds, which have functionalities in rings A and B similar to those of withaferin A(1), have been synthesized through the key intermediates cholesta-2,5-dien-1-one (10) and -2,4-dien-1-one (26). Electrophilic reactions of the steroidal 2,4-dien-1-one system were observed to occur stereoselectively on the β-side of the 4,5-double bond.