Synthesis of fructofuranosides: efficient glycosylation with N-phenyltrifluoroacetimidate as the leaving group

Fructofuranosyl trifluoroacetimidate 3 was demonstrated to be an effective glycosyl donor that exhibited good α-selectivity and good yield in fructosylation reactions. The reaction proceeds via neighboring group participation, which was proved by the isolation of a stable allylic orthoester intermediate.