Electrochemical synthesis of 5-trifluoroethyl dihydrobenzimidazo[2,1-a] isoquinolines from pendent unactivated alkenes via radical relay

An electrochemical radical relay method for direct access to 5-(2,2,2-trifluoro)ethyl dihydrobenzimidazo[2,1-a]isoquinoline derivatives from benzimidazole-tethered pendent unactivated alkenes in an undivided cell is developed. This method is applicable to Langlois reagent and difluoro analog, tolerates a wide range of functional groups and activated sp3 CH bonds, and obviates the need for external oxidants. The so-formed heterocycles display good fungicidal activities, especially against Botrytis.