Iterative α-Glycosylation Strategy for 2-Deoxy- and 2,6-Dideoxysugars: Application to the One-Pot Synthesis of Deoxysugar-Containing Oligosaccharides

This paper describes the development of an iterative and α-selective glycosylation method for 2-deoxyglycosyl and 2,6-dideoxythioglycoside donors based on the DMF modulation concept. We used NMR spectroscopy to probe the 2-deoxyglycosyl imidinium intermediate and elucidated the conditions to decrease the formation of glycal and thus to increase the reaction yields. Further elaboration of the glycosylation method opened the gate for an iterative one-pot synthesis of 2-deoxy- and 2,6-dideoxyglycoside-containing oligosaccharides.