Thiourea-catalyzed glycosylation: a breakthrough in stereoselective synthesis of oligosaccharides

Oligosaccharides are vital biomolecules that play an essential role in various biological functions. For studying biochemical processes, it is essential to have access to pure as well as structurally well-defined oligosaccharides. However, achieving high yields with excellent anomeric stereoselectivity through chemical glycosylation remains a challenging task for chemists. In the last few years, thiourea-catalyzed glycosylation has offered promising progress in carbohydrate chemistry due to its ability to catalytically activate glycosyl donors through non-covalent interactions, particularly hydrogen bonding. These thiourea catalysts have emerged as powerful organocatalysts, gaining popularity for facilitating highly stereoselective glycosylation reactions. This review highlights recent developments in thiourea-catalyzed glycosylation, a field still in its early stages but showing significant potential.