Nickel-Catalyzed Benzylation of Aryl Alkenes with Benzylamines via C-N Bond Activation.

We have developed the first example of nickel-catalyzed Heck-type benzylation of aryl olefins with various benzylamines as benzyl electrophiles, and the benzylic C-N bond cleavage was efficiently promoted by the amine-I2 charge transfer complex (CT complex). The combination of low-cost NiCl2 and I2 has been found to facilitate Heck reaction of tertiary benzylamines and alkenes into various benzyl-substituted alkenes in good to excellent yields. This unconventional Heck reaction is proposed to go through initially the formation of a benzylic radical via oxidative addition of the C-N bond with Ni(0), then capturing by aryl alkene via radical addition, followed by single-electron transfer redox and proton abstraction without oxidant and external base.