Synthesis of fluorescence-labelled disaccharide substrates of glucosidase II Original Research Article

The fluorescence-labelled disaccharides Glcα(1→3)GlcαOR and Glcα(1→3)ManαOR, both substrates for the glycoprotein-processing enzyme glucosidase II, were synthesised via the use of a n-pentenyl-derived linker at the anomeric position. This allowed incorporation of a pyrenebutyric acid label, via a sequence of oxidative hydroboration, mesylation, azide displacement, reduction with concomitant global deprotection, and peptide coupling. Selective activation of a fully armed thioglycoside in the presence of n-pentenyl glycosides was readily achieved by the use of methyl triflate as promoter.