Suzuki-Miyaura coupling reactions of aryl chlorides catalyzed by a new nickel(II) σ-aryl complex

A new nickel(II) sigma-aryl complex, trans-chloro(9-phenanthrenyl)bis(triphenylphosphine)nickel(II), was used as a precatalyst for the Suzuki-Miyaura coupling reactions of aryl chlorides. The catalytic conditions were optimized by investigating the cross-coupling of p-chloroanisole with phenylboronic acid. The results show that this complex is efficient for both electron-rich and electron-deficient aryl chlorides, though it gives better yields for activated arylboronic acids than deactivated ones. All isolated cross-coupled biaryl products have been characterized by 1H and 13C NMR, and their spectral data are consistent with those reported. Side products from the coupling of arylboronic acid with the precatalyst complex have also been isolated and characterized, which is helpful for understanding the coupling mechanism. Copyright (c) 2013 John Wiley & Sons, Ltd.