Synthesis of Bridged Steroids. VI. B-Norsteroids having a Gibbane B-C-D Ring System.(1). Synthesis of 5-Cyano-B-norsteroids via Hydrocyanation

Abstract

B-Nor-Δ⁴-3-ketosteroids such as compounds (11a, 11b, 11c, 17a, 17b and 23) weresynthesized starting from Δ⁵-3β-hydroxysteroids.
Hydrocyanation of these enones was investigated and by treatment with diethylaluminumcyanide only the 5β-vinyl derivatives (17a, 17b and 23) gave successfullythe corresponding 3-keto-5β-cyano compounds (18a, 18b, and 24a), intermediatesnecessary for the synthesis of B-norsteroids having cis-bicyclo [3, 2, 1] octane ring system.