2,3,4,6-Tetra-O-acetyl-α- d-gluco-pyranosyl azide

The CuI-catalysed 1,3-dipolar cyclo-addition of an azide and a terminal alkyne is becoming an increasingly popular tool for synthetic chemists. This is the most representative of the so-called click reactions and it is used to generate 1,4-di-substituted triazoles in high yield. During studies on such cyclo-addition reactions, a reduced reactivity of an -glucosyl azide with respect to the corresponding Β-anomer was observed. With the aim of understanding this phenomenon, the structure of the title compound, C14H19N3O9, has been determined at 140 K. The glucopyranosyl ring appears in a regular 4 C 1 chair conformation with all the substituents in equatorial positions, except for the anomeric azide group, which adopts an axial orientation. The observed bond lengths are consistent with a strong anomeric effect, which is reflected in a change in dipolar character and hence reduced reactivity of the -glucosyl azide. © 2008.