Process for synthesizing A-nor and A-nor-18-homo-steroids

A process for preparing A-nor and A-nor-18-homo-steroids of the formula:

• ##STR13## wherein n=1 or 0, R is methyl or ethyl;
• R.sub.1 is hydrogen or ##STR14## wherein A is lower alkyl, cyclo-alkyl or aryl;
• and R.sub.2 is hydrogen or methyl which comprises
• (a) reacting an optically active trans-fused bicyclic diketo-sulfone of the formula:
• ##STR15## with a 6-(1,3-dioxolan-2-yl)-3-oxoheptanoic acid methyl ester or with a 5-(1,3-dioxolan-2-yl)-3-oxohexanoic acid methyl ester to obtain a triketo derivative;
• (b) hydrolyzing, cyclizing and decarboxylating the product of step (a) to obtain an enone;
• (c) catalytically hydrogenating said enone to obtain a dione;
• (d) acid hydrolyzing to obtain a trione;
• (e) cyclizing the product of step (d) to obtain a mixture of isomeric enones;
• (f) subjecting said mixture to Birch reduction and oxidation to obtain the corresponding saturated 2,17-dione with the A:B trans stereochemistry;
• (g) ethynylating the product of step (f) to obtain a mixture of 2.alpha.- and 2.beta.-isomers;
• and
• (h) separating the isomers by chromatography.