The chemistry of castanospermine. Direct oxidation of the tetraacetate to the corresponding γ-lactam Original Research Article

From the products of oxidation of tetra-O-acetylcastanospermine (2) with N-bromosuccinimide, only the γ-lactam 11 was isolated (19%). Treatment of this lactam with DBU in dichloromethane afforded the elimination product 12, while deacetylation with sodium methoxide in methanol gave tetraol 13 together with diene 14. The X-ray crystal structure of compound 13 is reported.