Hyperbranched Polyester Supported Disaccharide Synthesis: The Effect of Loading Level on Glycosylation Efficiency

The efficiency of glycosylation of glycosyl acceptors supported on a hyperbranched polyester (Boltorn H-50) by an activated trichloroacetamidate donor was investigated as a function of the polymer loading. Loading of the hyperbranched polyester with an o-nitrobenzyl photolabile linker at 25% loading capacity (corresponding to 1.36 mmol/g) and using five equivalents of the glycosyl donor was optimal for quantitative transformation (>98%) at both the mono- and disaccharide stage. The disaccharide product obtained under these optimized conditions was isolated in 16% yield over five steps.