Polymeric DBU for Preparation of Glycosyl Trichloroacetimidates

Significance

The facile and practical procedure for preparation of glycosyl trichloroacetimidates was developed by using polystyrene-supported bases (5 substrates and 23 reaction conditions were examined). PS-DBU was proved to be the most efficient base in this protocol. The reactions of 2,3,4,6-tetra-acyloxy-α-d-glucopyranose derivatives (R = Ac or Bz) with trichloroacetonitrile proceeded smoothly in the presence of PS-DBU to give the corresponding α-anomers in quantitative yields. The trichloroacetimidates (α-anomers) were isolated without any chromatographic purification.