1,1-Dioxothiomorpholines with asymmetric environments: protecting group directed diastereoselectivity of glyco divinyl sulfone cyclization

Divinyl sulfones derived from pyranoside skeletons afforded 1,1-dioxothiomorpholine with predefined asymmetric environments. Although the exocyclic vinyl sulfone group easily reacts with primary amines, the intramolecular addition pattern of the secondary amine leading to the formation of the 1,1-dioxothiomorpholine derivative dramatically varied when benzylidene protection was replaced by benzyl protecting groups.