Synthesis of oligo-fructopyranoside with difructopyranosyl N-phenyltrifluoroacetimidate donor

The hexa-fructopyranoside was synthesized with N-phenyltrifluoroacetimidate glycosylation. The synthesis was achieved by regioselective glycosylation on the 1-OH of fructopyranosyl acceptor. Fructosyl oligosaccharides were elongated with β-(2 → 1)-difructopyranosyl unit in every two steps, without any further protection/deprotection step. This work proved N-phenyltrifluoroacetimidate glycosylation a practical method for oligo-fructopyranoside synthesis.