Highly selective lipase-mediated discrimination of diastereomeric 5,6-epoxysteroids

Abstract

Stereoisomerically pure 3[beta]-hydroxy-5,6-epoxysteroids were obtained by combining selective chemical methods for [alpha]- and [beta]-epoxidation of [Delta]5-unsaturated steroids with enzymatic stereoselective esterification of the 3[beta]-hydroxyl group. 5[beta],6[beta]-Epoxy-3[beta]-hydroxysteroids were efficiently acylated by Novozym 435 and lipase AK, whereas 5[alpha],6[alpha]-epoxy-3[beta]-hydroxysteroids were good substrates for Candida rugosa lipase. Mild enzymatic deacylation of the 3[beta]-acetoxy group in the presence of the epoxy functionality was also accomplished by C. rugosa lipase-mediated hydrolysis.