Totally synthetic steroid heterocycles. Part 2. Stereochemistry of hydride reduction of 16-oxa- and 16-thia-8,14-didehydro-D-homoestrone 3-methyl ether and related compounds

Abstract

The stereochemistry of carbonyl reduction of 16-oxa- and 16-thia-8,14-didehydro-D-homoestrone derivatives (1)–(3) was studied using various hydrides. Some related compounds (4)–(8) were also examined for comparison. The observed stereochemical results are tentatively interpreted in terms of control of steric approach to the ring carbonyls in different conformations by the ring heteroatoms involved. Ring deformation caused by introduction of a sulphur atom often reverses the steric course of carbonyl reduction in steroids.