Recent Advances in O-Glycosylation

Abstract

The preparation of defined carbohydrate structures continues to rely heavily on efficient methods for forming O-glycosidic bonds. Although many established glycosylation protocols are available, achieving consistent stereochemical control remains difficult, especially when structurally complex donors and acceptors are involved. In recent years, continued improvements in reaction design including strategic use of protecting-groups to modulate substrate reactivity have provided more reliable ways to address long-standing challenges related to selectivity, substrate scope, and practical execution. Recent developments have introduced novel donor classes, alternative activation modes and reaction conditions that allow glycosylation to proceed with fine control under milder conditions. At the same time, growing mechanistic insights have supported the design of strategies for challenging glycosidic linkages and more efficient oligosaccharide assembly. In this chapter, we will discuss recent advances in O-glycosylation, with emphasis on new methodological developments in this area, stereo-controlled glycosidic bond formation, and representative applications in complex carbohydrate synthesis reported during the last four years.