Synthesis of pregnenoic acid derivatives possessing structural elements of prostaglandins

Pregneoic acid derivative V in which the character of functional groups and distances between them (expressed in terms of C-C bonds) resemble those occurring in prostaglandins has been synthetised. 3beta-Hydroxyandrost-5-en-17-one acetate VII was converted to ethyl 3beta-acetoxypregn-5-en-21-oate XIIa via a Reformatsky reaction followed by dehydration of adduct VIIIa and selective hydrogenation of the diene X. Compound XIIa was then transformed into trienone XIII by oxidation of the 3beta-hydroxy-5-ene XIIc with DDQ. The trienone XIII was subsequently epoxidised with alkaline hydrogen peroxide and m-chloroperbenzoic acid to give diepoxide XV which was reduced with aluminum amalgam to the final product V.