Cross Coupling of Non-Activated Alkyl Halides by a Nickel Pincer Complex
Non-activated alkyl halides are challenging substrates for cross-coupling reactions because they are reluctant to undergo oxidative addition and because metal alkyl intermediates are prone to β-H elimination. Despite recent progress, well-defined catalysts are rare. We recently prepared Ni complexes with a chelating pincer-type bis(amino)amide ligand. The chloride complex [(MeNN2)NiCl] is an active (pre)catalyst for the coupling of non-activated alkyl halides with alkyl, aryl, and heteroaryl Grignard reagents. The catalysis tolerates a wide range of functional groups such as keto, ester, amide, acetal, indole, furan, nitrile, etc. The Ni complex also catalyzes direct alkylation of alkynes and aromatic heterocycles.