• carbohydrates;
  • glycosylation;
  • neighboring-group effects;
  • stereoselectivity;
  • substrate concentration


This study develops an operationally easy, efficient, and general 1,2-trans β-selective glycosylation reaction that proceeds in the absence of a C2 acyl function. This process employs chemically stable thioglycosyl donors and low substrate concentrations to achieve excellent β-selectivities in glycosylation reactions. This method is widely applicable to a range of glycosyl substrates irrespective of their structures and hydroxyl-protecting functions. This low-concentration 1,2-trans β-selective glycosylation in carbohydrate chemistry removes the restriction of using highly reactive thioglycosides to construct 1,2-trans β-glycosidic bonds. This is beneficial to the design of new strategies for oligosaccharide synthesis, as illustrated in the preparation of the biologically relevant β-(1[RIGHTWARDS ARROW]6)-glucan trisaccharide, β-linked Gb3 and isoGb3 derivatives.