Michael-type addition to 2-nitrogalactal - A simple method to access 1,1-linked oligosaccharides

Abstract

Anomeric O-unprotected sugars add to 3,4,6-tri-O-benzyl-2-nitro-D-galactal to accomplish nitro group-containing 1,1-linked oligosaccharides in respectable yields with good selectivities. A 1:1 mixture of toluene and n-heptane has been found as the appropriate solvent system for these Michael-type additions. The nitro group-containing 1,1-linked oligosaccharides are easily convertible into interesting trehalosamine analogues.