STEROID SPIROLACTONIZATION

A steroid comprising a 17-spirolactone or corresponding open lactone structu re is obtained by carbonylation of a 17-alkenyl or 17-alkynyl substrate. A 17- alkenyl intermediate may be prepared by semi-hydrogenation of a 17-alkynyl group. Multiple reaction schemes are disclosed for preparation of a 3-keto- 9, 11-epoxy-17-spirolactone steroid such as eplerenone. Novel intermediates a re also disclosed, as well as steps for forming such novel intermediates, or converting them to further intermediates or products, by semi-hydrogenation, carbonylation, 6, 7-dehydrogenation, furylation or other transformations or combinations thereof.