A two-step synthesis of the pregnane and corticoid side-chains

Abstract

Zinc converts the 17α-ethynyl carbinol acetate (1) by a reductive process accompanied by rearrangement and elimination, into the allenyl steroid (2a), a useful intermediate for the preparation of the corticoid chain by osmylation, and of 17α-hydroxy-20-oxo-pregnanes by peracid oxidation.