SYNTHESIS OF 19-HYDROXY-1-BETA,19-CYCLOSTEROIDS

19(RIS)-Substituted 1 beta,19-cyclo-5 alpha-steroids have been synthes ized by reductive cyclization of 3,17-dioxo-5 alpha-androst-1-en-19-al with zinc in aqueous acetic acid or lithium in ammonia, The major pro duct from the zinc reaction, the 19(R)-cyclopropanol, exists in equili brium with the 3-hemiketal; the minor product, the 19(S)-alcohol, is i solated as the silyl ether and deprotected to give the 19(S)-cycloprop anol, The major product from the lithium-ammonia reaction is the 19(S) -cyclopropanol. Neither acid nor base treatment of the 19(R)- and 19(S )-alcohols gives evidence of their interconversion, structures are est ablished by NMR measurements.