From Dimethylamine to Pyrrolidine: The Development of an Improved Nickel Pincer Complex for Cross-Coupling of Nonactivated Secondary Alkyl Halides

Replacement of a dimethyl amino group of the amidobis(amine) nickel(II) pincer complex (1), [((N2N)-N-Me)-Ni-Cl], by a pyrrolidino group resulted in a new nickel(II) pincer complex (2), [((PNNN)-N-yr-N-Me)Ni-Cl]. Complex 2 is an efficient catalyst for Kumada and Suzuki-Miyaura cross-coupling of nonactivated secondary alkyl halides, while complex 1 is largely inactive. The significant activity difference is tentatively attributed to a minimal structural difference, which leads to a more hemilabile ligand.