Totally synthetic steroid heterocycles. Part 3. Stereochemical course of oxidation of sulphur in 16-thia-8,14-didehydro-D-homoestrone 3-methyl ether and its derivatives

Abstract

The stereochemistry of oxidation at sulphur of the steroidal systems 16-thia-8,14-didehydro-D-homoestrones (1a–e) was studied with the oxidants sodium metaperiodate and m-chloroperbenzoic acid. The configurational assignments of the α- and β-oxides obtained are based on i.r. (intramolecular hydrogen bonding) and n.m.r. data. The direction and degree of stereoselectivity in the oxidation contrasts with that observed for thians. A marked directive effect is observed for peracid oxidation of the α-hydroxy-sulphide (1b), leading to the α-oxide (2b) in a highly stereoselective manner.