PIP: The syntheses of several 1,2alpha-methylene steroids containing a sp irotetrahydrofuran ring at the 17 position are described. The antiandro genic activity of these compounds was determined in immature male castrate rats treated with testosterone enanthate. The ability of the compounds to antagonize the androgen-stimulated weight gain of the simin al vesicle and ventral prostate serves as a measure of their activity. From the results, the antiandrogenic activity associated with the Tetrah ydrofuran-2'-spiro-17 androstenones I and II has been increased by addit ion of a 1,2alpha-methylene function and by incorporation of either a 6- chloro-delta6 or 6,7alpha-difluoromethylene group to the basic steroid s keleton. These compounds show minimal other hormonal activity. Tert-Butyl chromate oxidation of the spirotetrahydrofuran XIII affords the corresponding spirolactone XIV in high yield.