We have developed methods to prepare regioselectively acylated ethyl thioglycosides of β-D-GlcA(1→4)-2-azido-2-deoxy-D-Glc from cellobiose to be used as disaccharide building blocks in synthesis of heparin and heparan sulfate structures. Investigations will be presented into the coupling of these disaccharide building blocks to afford α-linked tetra- and hexasaccharides (Fig. 1). Although both donor (2-azido) and acceptor (uronic acid) are deactivated, conditions could be found to achieve glycosylations in high yields and good α-selectivity.
