2,3,4,6-Tetra-O-acetyl-alpha-D-glucopyranosyl azide

The Cu(I)-catalysed 1,3-dipolar cycloaddition 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-disubstituted triazoles in high yield. During studies on such cycloaddition reactions, a reduced reactivity of an alpha-glucosyl azide with respect to the corresponding beta-anomer was observed. With the aim of understanding this phenomenon, the structure of the title compound, C(14)H(19)N(3)O(9), 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 alpha-glucosyl azide.