Conversion of Dehydroabietic Acid into a Steroid Skeleton : Formation of the A-Ring. II

Abstract

Conversion of dehydroabietic acid (1) to a steroid skeleton was attempted. The oxo ester (3), an important intermediate in the synthesis of 4, was synthesized from 7 having a double bond in the A ring. It was confirmed that the oxo ester (3) has the α configuration at the 5-position.