Glycosyl Oxazolines Serve as Active Donors for Iterative Synthesis of Type I Oligosaccharides

Abstract

Synthesis of Galβ1→3GlcNAc-repeating saccharides is limited mainly by the formation of less-reactive oxazolines. We herein report an expeditious approach that requires trichloroacetyloxazolines as reactive glycosyl donors. Using only two disaccharide building blocks, the iterative oxazoline formation and glycosylation synthesized hexa- and octasaccharides with overall yields of 47% and 26% in four and six steps, respectively.