Studies Toward the Synthesis of Contignasterol: Functionalization of the Steroidal A,B Ring System.

The synthesis of androstane-3α,4β,6α,7β-tetrol-17-one (2), a potentially key intermediate for the preparation of contignasterol (1), was achieved by functionalization of the A,B-ring portion of the readily available androst-4-ene-3,17-dione (3).