Control of disaccharide conformation through pi-stacking

Abstract

The conformations of a series of derivatives of the disaccharide α-L-fucopyranosyl-(1→3)-2-acetamido-2- deoxy-D-glucopyranoside, part of the Le^x determinant, were studied by molecular modelling using the MM3* forcefield and by ¹H NMR spectroscopy. Unusually shielded O-benzyl protons were observed in the ¹H NMR spectrum of phenyl 2,3,4-tri-O-benzyl-α-L-fucopyranosyl-(1→3)-2-deoxy-2-phthalimido-1-thio-α-D-glucopyranoside and assigned to the 2-O-benzyl group. This observation was explained by a shift in the population of the conformational mixture present about the glycosidic linkage from the positive ψ region in the unsubstituted disaccharide to the negative ψ region induced by π-stacking between the phthalimide and the 2-O-benzyl phenyl ring. The experimental nuclear Overhauser enhancements confirm the accuracy of the calculations.

More information

Identifiers

Catalogue record

Export record

Altmetrics