The Synthesis of A-Homo-B-norandrostanes: The Effect of a Hydroxyl on the Course of Hydrogenation of the ∆9-Double Bond

Abstract

Acetolysis of 6β-mesyloxy-5-methyl-19-nor-5β-steroids (e.g. 10) was proved to yield 4a-homo-7,19-dinor compounds (e.g. 9) with a hydroxy group in the position 4aα. Hydrogenation of these compounds affords 9β,10β-dihydro derivatives (e.g. 12) predominantly, corresponding 9α,10α isomers (e.g. 13) are only formed in low yields. This sequence was used for the synthesis of analogues of androgen hormones 4aα-hydroxy-4aβ-methyl-4a-homo-7,19-dinor-5α,9β,10β- androstane-3,17-dione (27), 4aα,17β-dihydroxy-4aβ,17α-dimethyl-4a-homo-7,19-dinor-5α,9β,10β-androstan-3-one (28) and 4aα,17β-dihydroxy-4aβ-methyl-4a-homo-7,19-dinor-5α,9β,10β-androstan-3-one (29).