Ruthenium-Catalyzed Oppenauer-Type Oxidation of 3beta-Hydroxy Steroids. A Highly Efficient Entry into the Steroidal Hormones with 4-En-3-one Functionality

J Org Chem. 1996 Sep 20;61(19):6587-6590. doi: 10.1021/jo960361q.

Abstract

Oxidation of 5-unsaturated 3beta-hydroxy steroids 1 to the corresponding 4-en-3-one derivatives 2 can be performed efficiently by acetone at reflux in the presence of a catalytic system consisting of either (PPh(3))(3)RuCl(2) (3) and K(2)CO(3) or [(C(4)Ph(4)COHOCC(4)Ph(4))(&mgr;-H)][(CO)(4)Ru(2)] (4). The reaction proceeds via a ruthenium-catalyzed dehydrogenation of 1 and subsequent hydrogen transfer to acetone with concomitant double bond migration.