N-substituted pyrrolidin-3-ones as heterocyclic building blocks. Enantioselective synthesis of 8-epi- and 1,8,8a-triepi-castanospermine

Abstract

Regioselective aldol reaction of dianion 1 with aldehyde 5 provides the basis of a new approach to the construction of polyhydroxy indolizidines and the application of this methodology to the synthesis of 8-epicastanospermine 11 and 1,8,8a-triepicastanospermine 12 is described.