4-(2′-Phenylethynylphenyl)phenyl glycosides as glycosylation donors.

We have disclosed that 3,5-dimethyl-4-(2′-phenylethynylphenyl)phenyl (EPP) glycosides could be employed as glycosylation donors via an unprecedented activation mechanism. Here we report that the EPP glycosides without the 3,5-dimethyl groups, which were previously installed to prevent the plausible Friedel-Crafts-type side reactions, can also undergo glycosylation effectively. Employing such an EPP 2-azidoglucoside as donor, the construction of the challenging α-GlcN-(1→4)-GlcA linkage is realized, leading to a heparin trisaccharides precursor. [ABSTRACT FROM AUTHOR]