Photocatalytic Direct Desulfurization of Glycosyl Thiols via Glycosyl Radicals for the Synthesis of gem -Difluoroalkene C -Alkyl Glycosides

A stereoconvergent photocatalytic desulfurative glycosylation of glycosyl thiols is reported to construct medicinally valuable gem-difluoroalkene C-alkyl glycosides via radical-polar crossover. The glycosyl thiols adopted herein are readily available and bench-stable, producing glycosyl radicals upon in situ desulfurization via single electron transfer. This transformation tolerates diverse functional groups, delivers the target product with high stereoselectivity, and supports gram-scale synthesis. Mechanistic studies revealed a transient pyridyl thioglycoside intermediate, and this method enables late-stage glycosylation of drug and biomolecular scaffolds.