Stereoselective Photoredox-Catalyzed Vinylations to Function-alized Alkenes and C-Glycosides

We have disclosed two efficient radical-mediated C-C couplings through photoredox-catalyzed reactions of 4-alkyl-1,4-DHPs and vinylbenziodoxol(on)es (VBX, VBO). This transition-metal-free and mild photocatalytic method has excellent functional group tolerance and affords vinylated products in good yields, with excellent stereoselectivities where the alkene configuration is retained. The utility of the methodology is demonstrated by the diastereoselective synthesis of C-vinyl glycosides. Preliminary mechanistic studies signify that the C-C bond formation proceeds through a concerted radical coupling transition state.