Selective Glycosylations with Deoxy Sugars

Abstract

This chapter focuses on recent developments, mostly within the past 10 years, in the development of direct methods to construct 2-deoxy-sugar linkages. 2-Deoxy-sugars possess several characteristics that make their synthesis unique from and, at times more challenging than, classical oligosaccharide synthesis. In addition to the issues associated with deoxy-sugar stability, deoxy sugars tend to undergo nonselective glycosylations with alcohol nucleophiles in the absence of directing groups. One of the challenges in developing selective glycosylations with deoxy sugars is directly a result of their deoxygenation. While glycosyl halides are commonly used as donors for a variety of glycosidic linkages, the use of 2-deoxy-glycosyl halides is far more limited, owing in part to their lability. 2-Deoxy-glycosyl chlorides are the most stable species and have been used as intermediates in the synthesis of other glycosyl donors, such as glycosyl phosphonates. Reagent-controlled approaches have also been applied to the construction of α-linked deoxy sugars.