Palladium-catalysed C-H glycosylation for synthesis of C-aryl glycosides

C-aryl glycosides are widely found in nature and play important roles in drug design. Despite the significant progress made over the past few decades, efficient and stereoselective synthesis of complex C-aryl glycosides remains challenging, lagging far behind the state of the art of the synthesis of O- or N-glycosides. Here, we report a simple and powerful bioinspired strategy for the stereoselective synthesis of C-aryl glycosides via palladium-catalysed ortho-directed C(sp(2))-H functionalization of arenes and heteroarenes with easily accessible glycosyl chloride donors. The catalytic palladacycle intermediate generated via C-H palladation provides a soft aryl nucleophile that can react with glycosyl oxocarbenium ion partners with high efficiency and excellent stereocontrol. The method can be applied to a wide range of arene and heteroarene substrates, glycosyl chloride donors and auxiliary groups. It can simplify the synthesis of a variety of complex C-aryl glycosides and offers a tool for late-stage modification of drug molecules.