A mechanistic study: Nucleophile dependence in glucosylations with glucosyl bromides

Glycosylations using glucosyl bromides and various promoters (Et4NBr, HgBr2, or AgOTf) were investigated, competitively and kinetically. The reactions were found to be dependent in both glucosyl bromide and nucleophilic concentration, indicating a SN2-type rate, determining step. For the AgOTf promoted reaction an ion pair mechanism involving glucosyl triflates is suggested.