An efficient procedure for the synthesis of 2,3-unsaturated-O-glycosides: TiCl3(OTf) as the catalyst for type I Ferrier rearrangement

An efficient type I Ferrier rearrangement reaction system for the synthesis of 2,3-unsaturated-O-glycosides has been established by using TiCl3(OTf) as the catalyst. A series of 2,3-unsaturated-O-glucosides were prepared from 3,4,6-tri-O-acetyl-d-glucal in good yield and high anomeric selectivity.

Twenty-one examples. Yield upto 90%. Anomeric selectivity: α:β 2/1-100/0.