Photocatalyzed Hydro-acrylonitrilation of Alkenes

The catalytic cyanation of alkene feedstocks is a powerful method for introducing highly versatile alkenyl nitrile moieties into organic molecules. These reactions have traditionally relied on transition metal catalysts, hazardous nitrile sources, or prefunctionalized alkenes, which have restricted their potential application in drug discovery. Here, we present the first photocatalytic hydro-acrylonitrilation of free alkenes using stable 4-cyano-3-oxotetrahydrothiophene (c-THT) as the cyano source to produce fused alkenyl nitriles with broad substrate scope and excellent functional group tolerance. Unlike previous polar catalysis, c-THT was first applied in visible-light catalysis as an acrylonitrile surrogate, allowing this radical-mediated reaction to occur under operationally simple and mild conditions and enabling numerous functionalized activated and nonactivated alkenes to proceed acrylonitrilation in a highly efficient manner. The synthetic utility was further demonstrated by the gram-scale preparation and downstream synthetic elaboration toward various valuable building blocks.