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.