Stereoselective<i>C</i>‐Aryl Glycosylation by Catalytic Cross‐Coupling of Heteroaryl Glycosyl Sulfones
Quanquan Wang, Boon Chong Lee, NingXi Song, Ming Joo Koh
Abstract
Stereoselective C-glycosylation reactions are increasingly gaining attention in carbohydrate chemistry because they enable glycosyl precursors, readily accessible as anomeric mixtures, to converge to a single diastereomeric product. However, controlling the stereochemical outcome through transition-metal catalysis remains challenging, and methods that leverage bench-stable heteroaryl glycosyl sulfone donors to facilitate glycosylation are rare. Herein, 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 through 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 was possible for key sugar residues.