We have developed a stereoselective, glycosyl radical-based method for the synthesis of C-alkyl glycosides via a photomediated defluorinative gem-difluoroallylation reaction. We demonstrate for the first time that glycosyl radicals, generated from glycosyl bromides, can readily participate in a photomediated radical polar crossover process, affording a diverse array of gem-difluoroalkene containing C-glycosides. Notable features of this method include scalability, mild conditions, broad substrate scope, and suitability for the late-stage modification of complex molecules.

We have developed a cyanide-free strategy for the synthesis of glycosyl carboxylic acids, which can provide 1,2-trans or 1,2-cis glycosyl carboxylic acids and is compatible with common protecting groups. The synthetic utility was demonstrated by the synthesis of 12 unreported glycosyl acids and the total synthesis of scleropentaside A.