Aromatic C-H Borylation by Nickel Catalysis

The first nickel-catalyzed aromatic C-H borylation is described. In the presence of catalytic amounts of [Ni(cod)(2)], tricyclopentylphosphine, and CsF, benzene and indole derivatives can be borylated with B(2)pin(2). The N-heterocyclic carbene IPr was also found to be an effective ligand. Kinetic isotope effect experiments showed that C-H cleavage is likely involved in the rate-determining step.