Utilization of Protopine and Related Alkaloids. XII. An Improved Route to an Analog of the Alkaloid Corynoline

Abstract

Photolysis of dihydroisoquinoline (2) in the presence of nitrosobenzene gives the epoxyimine (10), sodium borohydride reduction of which affords the aniline (14). Reaction of the dehydro compound (17) derived from 14 with performic acid followed by hydrolysis provides the diol (20). Hydrogenolysis of 20 over a palladium catalyst affords the corynoline analog (7). All compounds are formed under strictly stereoselective control.