Synthesis of a d -Glucopyranosyl Azide: Spectroscopic Evidence for Stereochemical Inversion in the SN2 Reaction

Stereospecific S N 2 conversion of configurationally pure acetobromoglucose (2,3,4,6-tetra- O -acetyl-α- d -glucopyranosyl bromide) to the corresponding β- d -glucopyranosyl azide is a useful exercise in the advanced organic undergraduate teaching laboratory. The procedure is safe and suitable for small-scale implementation, and firm proof of the stereochemical change is obtained from 1 H NMR coupling constants. The exercise provides students with experience in using important chiral pool natural product derivatives, reaction analysis by TLC, as well as careful product isolation, purification, and spectroscopic identification.