Synthesis of Bridged Steroids. I. Steroids having a Bridged Bicyclo [3. 2. 1] octane Ring System of the Phyllocladene Type

Abstract

Steroidal derivatives having a bicyclo [3. 2. 1] octane bridged ring of the phyllocladene type on the A ring such as compounds (IVa), (IVb), (XXIV) and (VIIIa) were synthesized starting from 5α-cyanocholestan-3-one by three routes. The route consisting of conversion of the cyano group into an acetyl group, and subsequent cyclization was found to be most preferable for the synthesis.