Short, asymmetric synthesis of epi-morphine ACNO analogues

The short synthesis of ACNO analogues of morphine and the development of an asymmetric version of this polycyclization methodology was investigated. It was found that the oxygenated five-membered ring of the compound could be derived from the imine which may originate from tetracycle by oxidation of the aniline nitrogen and chemoselective removal of the ketone function. An enantioselective version of this methodology was also delineated for the rapid assembly of the ACNO analogues. The completion of the asymmetric synthesis of intermediate compound required the removal of the carboxymethyl auxiliary. The results show that tetracycle compound could be isolated in a overall yield of 67% from applying this methodology to the synthesis of naturally occurring opioids.