Glycosynthases are becoming important enzymatic tools for the synthesis of oligosaccharides. Herein, we explore for the first time the synthesis of alpha-glycoconjugates using a alpha-glycosynthase in green solvents. Using this biocatalyst, beta-Gal-N3 as donor, pNP-Glc and pNP-Man as acceptors, and green co-solvents we obtained high yields and excellent selectivities in the synthesis of alpha-glycoconjugates. In addition, reaction scale-up is feasible and co-solvent can be recovered and reused, increasing the sustainability of the reaction process. The results demonstrate that the combination of a glycosynthase and a green solvent is a promising alternative for the synthesis of glycoconjugates. The non-hydrolytic capability of this enzyme on the product obtained is a key feature that can be expanded to other glycosynthases.
