Steroids and Walden inversion. Part LXIX. Substitution reactions of the 5α-androstan-11-ols

Abstract

5α-Androstan-11α-ol (IV) on treatment with phosphorus pentachloride does not undergo substitution; elimination occurs instead to give 5α-androst-9(11)-ene and its chlorine addition product 9α,11β-dichloro-5α-androstane. However treatment of the alcohol (IV) with thionyl chloride results in substitution with retention of configuration to give 11α-chloro-5α-androstane (40%) and 5α-androst-9(11)-ene (22%). Treatment of 5α-androstan-11β-ol with phosphorus pentachloride or with thionyl chloride yields only 5α-androst-9(11)-ene.