Synthesis of D-seco-13α-Androst-5-ene Derivatives

3β-Hydroxy-16,17-seco-13α-androsta-5,16-dien-17-al was obtained from 3β-acetoxyandrost-5-en-17-one in six steps with a Grob fragmentation as the key step. This seco-steroid, containing a formyl group and an unsaturated side-chain in a sterically favourable cis position, is a useful synthon for the synthesis of novel heterocycles condensed to the 3β-hydroxy-13α-androst-5-en-17-one skeleton.