RU-16117 is synthesized from D9(11)-estradiol (I). After protecting the hydroxyl groups by the formation of a benzyl ether (II), the double bond is hydrated by hydroboration, followed by oxidation with hydrogen peroxide in alkali. The alcohol thus formed (III) is treated with sodium hydride and then methyliodide (IV). After deprotection of the 3 and 17 hydroxyl groups (V), the C-17 hydroxyl is oxidized to a ketone by chromic oxidation (VI) and the 17-alpha-ethynyl group is introduced directly with potassium acetylide.