No abstract

Acid-catalyzed treatment of 1,9,10,10a-tetrahydro-3(2H)-phenaiithrenones with ethylene glycol led to kefcalization with accompanying double-bond migration. Catalytic hydrogenation, followed by cleavage of the ketals gave the corresponding B/C-cfs hexahvdrophenanthrenones. Metal in liquid ammonia reduction of the unsaturated ketals followed by hydrolysis gave the B/C-trans hexahydrophenanthrenones. Both series of compounds were converted to 2-alkyloctahydro-3-ketophenanthrenes which were of interest as nitrogen-free analogs of tetrabenazine.