Sterol synthesis. Chemical synthesis of 3β-benzoyloxy -14α, 15α-epoxy-5α-cholest-7-ene, a key intermediate in the synthesis of 15-oxygenated sterols☆

Abstract 3β-Benzoyloxy-14α, 15α-epoxy-5α-cholest-7-ene was obtained in 96% yield upon treatment of 3β-benzoyloxy-5α-cholesta-7, 14-diene with m -chloroperbenzoic acid. The Δ 7 -14 α , 15α-epoxy-steryl ester provides a useful intermediate for the syntheses of sterols with an oxygen function at carbon atom 15. For example, treatment of 3β-benzoyloxy-14α, 15α-epoxy-5α-cholest-7-ene with methanolic hydrochloric acid gave 3β-benzoyloxy-5α-cholest-8(14)-en-15-one in 82% yield.