ESTRA-1,3,5(10),15-TETRAENES .1. BIRCH REDUCTION

The addition of organolithium reagents to 3-methoxyestra-1,3,5(10),15-tetraen-17-one (3) yielded a series of 17-substituted ∆15 derivatives (6). Birch reduction of 6a and 6b at -78° led to reduction of ring A without reduction of the ∆15 double bond. Oppenauer oxidation at room temperature of the intermediate 3-methoxyestra-2,5(10),15-trien-17β-ol (10) afforded the ketone 11 which was converted to a series of active progestins. The hypocholesteremic and estrogenic activities of the intermediate aromatic steroids are reported. A simple procedure for ethynylation of base-sensitive ketones is described. © 1968, American Chemical Society. All rights reserved.