Glycosyl Azides – An Alternative Way to Disaccharides

Glycosyl azides are shown to be efficient donors for β‐galactosidases, β‐glucosidases and α‐mannosidases. Only α‐galactosidases do not cleave the respective glycosyl azide 1 and, moreover, they exhibit competitive inhibition (especially α‐galactosidase from Talaromyces flavus ). High water solubility and ready synthesis of glycosyl azides enable transglycosylation reactions even with difficult acceptors like N ‐acetyl‐ D ‐mannosamine in good yields. The versatility of glycosyl azides was demonstrated in the synthesis of five disaccharides – two of them are described for the first time. All the reactions were highly regioselective, yielding β(1→6) isomers. β‐Galactosidase from E. coli proved to have the best synthetic capabilities. The present study shows that glycosyl azides are a valuable alternative to common p ‐nitrophenyl glycoside donors and in many synthetic reactions.