Glycosyl Donor

Phenyl N-benzyl-2-amino-4,6-O-benzylidene-2-N,3-O-carbonyl-2-deoxy-1-thio-β-D-glucopyranoside (1) is a glycosyl donor developed by Mababe et al., which is used as a building block for 1,2-cis glycosidic bond formation of an amino sugar. For example, reductive benzylidene acetal ring opening of 1 gives 2. Subsequently, 2 is converted either to glucosamine derivative 3 via chloroacetylation or to galactosamine derivative 4 via stereoinversion and acetylation. 3 or 4 react with glycosyl acceptor 5 to give disaccharide 6 or 7, respectively, with high α-selectivity. As amino sugars having 1,2-cis glycosidic bonds exist in many bioactive sugar chains such as heparin, application of these donors to bioactive oligosaccharide synthesis is promising.