Synthesis of 2-Deoxyglycosides

Recent developments in the synthesis of natural products containing 2-deoxyglycosides are reviewed. Oligosaccharides and glycoconjugates containing 2-deoxyglycosides are difficult to prepare owing to the high reactivity of the deoxy sugar monosaccharides. As a consequence, glycosylation protocols that have been reliably employed on fully substituted sugars are not always applicable to the stereoselective synthesis of 2-deoxy sugars; thus, alternative synthetic methods have been developed to address this challenge. In the past, glycals and glycosyl donors with prosthetic groups were commonly used despite their limitations in substrate scope. While these methods are still in use, in the last two decades, novel donors and methodologies have been established, often with the assistance of mechanistic studies. This latest development has enabled the mild and selective generation of 2-deoxy oligosaccharides, particularly those found in complex natural products and their analogs.