Stereoselective C-Aryl Glycosylation by Catalytic Cross-Coupling of Heteroaryl Glycosyl Sulfones.

Abstract

Stereoselective C-glycosylation reactions are increasingly gaining attention in carbohydrate chemistry because they enable glycosyl precursors, easily accessible as anomeric mixtures, to converge to a single diastereomeric product. However, controlling the stereochemical outcome via transition metal catalysis remains challenging, and methods that leverage bench-stable heteroaryl glycosyl sulfone donors to facilitate glycosylation are rare. Here, we show two complementary nonprecious metal catalytic systems, based on iron or nickel, which are capable of promoting efficient C-C coupling between heteroaryl glycosyl sulfones and aromatic nucleophiles or electrophiles via distinct mechanisms and modes of activation. Diverse C-aryl glycosides were secured with excellent selectivity, scope, and functional group compatibility, and reliable access to both α and β isomers could be achieved for key sugar residues.