Studies in the (+)-Morphinan Series I. An Alternative Conversion of (+)-Dihydrocodeinone into (+)-Codeine

A novel four-step transformation o f (+)-dihydrocodeinone (1) t o unnatural (+)-codeine (5) a!-carbethoxy-7-phenylselenonordihydrocodeinone (3) (40% o v e r a l l y i e l d ) i s described.The s t r u c t u r e and absolute c o n f i g u r a t i o n of 3 were confirmed by s i n g l e c r y s t a l X-ray analysis.