Stereoselective Preparation of α- C-Vinyl/Aryl Glycosides via Nickel-Catalyzed Reductive Coupling of Glycosyl Halides with Vinyl and Aryl Halides.

Facile preparation of the α- C-vinyl and -aryl glycosides has been developed via mild Ni-catalyzed reductive vinylation and arylation of C1-glycosyl halides with vinyl/aryl halides. Good to high α-selectivities were achieved for C-glucosides, galactosides, maltoside, and mannosides, which were dictated by the employment of pyridine type ligands. As such, the present work represents unprecedented control for a high level of α-selectivity for C-vinyl-glucosides using cross-coupling approaches and offers hitherto optimal α-selective preparation of C-aryl glucosides via catalyst-controlled coupling strategies.