The selective oxidation of protected cholestanol derivatives using the Gif system

Abstract
Oxidation of 3β,5α6β-triacetoxycholestane using the Gif system (iron cluster–metallic zinc–pyridine–aqueous acetic acid) gives, as major product, the side-chain fission ketone 3β,5α,6β-triacetoxy-5α-pregnan-20-one. The 15- and 16-keto derivatives of the parent triacetate are also formed. Comparable results are obtained in the oxidation of cholestanol acetate and of acetoxycholestan-6-one ethylene ketal.