Influence of acyl groups on glucopyranoside reactivity in Lewis acid promoted anomerisation

Abstract Lewis acid promoted anomerisation has potential in O - or S -glycoside synthesis. Herein, the anomerisation kinetics of thirty-one β- d -glucopyranosides was determined to determine how particular acyl protecting groups and their location influence reactivity towards a Lewis acid promoted reaction. The replacement of acetyl groups with benzoyl groups led to reduced reactivity when located at O-3, O-4 and O-6. However a reactivity increase was observed when the acetyl group was replaced by a benzoyl group at O-2. The 2,3,4,6-tetra- O -(4-methoxy)benzoate had an ∼2-fold increase in rate when compared to the tetrabenzoate.