β-Glycosyl Trifluoroborates as Precursors for Direct α-C-Glycosylation: Synthesis of 2-Deoxy-α--glycosides.

-Glycosides are metabolically stable mimics of natural -glycosides and are expected to be useful tools for investigation of the biological functions of glycans. Here, we describe the synthesis of a series of aryl and vinyl -glycosides by stereoinvertive sp-sp cross-coupling reactions of 2-deoxyglycosyl boronic acid derivatives with aryl or vinyl halide, mediated by a photoredox/nickel dual catalytic system. Hydrogenation of the vinyl -glycosides afforded C-linked 2'-deoxydisaccharide analogues.