Synthesis of 7α-substituted androstenediones by a 1,4-conjugate addition approach

Oxidation of enol lactone 9 with Pd(OAc)2 gave enone 8, which underwent stereoselective 1,4-conjugate addition with a series of cuprates affording the 7α-ketones 10–12 in excellent yield. Subsequent saponification and cyclization gave enol lactones 13–15, which can be transformed into the testosterone derivatives by treatment with 2.1 eq of LiCH2P(O)(OMe)2.