[(NHC)PdCl<sub>2</sub>(Aniline)] Complexes: Easily Synthesized, Highly Active Pd(II)–NHC Precatalysts for Cross-Coupling Reactions
Qinqin Xia, Shicheng Shi, Pengcheng Gao, Roger A. Lalancette, Roman Szostak, Michal Szostak
Abstract
We report the synthesis, characterization, and reactivity of [(NHC)PdCl2(aniline)] complexes. These well-defined, air- and moisture-stable catalysts are highly active in the Suzuki–Miyaura cross-coupling of amides by N–C(O) activation as well as in the Suzuki–Miyaura cross-coupling of esters, aryl chlorides, and Buchwald–Hartwig amination. Most crucially, this study introduces broadly available anilines as stabilizing ligands for well-defined Pd(II)–NHC catalysts. The availability of various aniline scaffolds, including structural and electronic diversity, has a significant potential in fine-tuning of challenging cross-couplings by Pd–NHCs. The parent catalyst in this class, [Pd(IPr)(AN)Cl2], has been commercialized in collaboration with Millipore Sigma, offering broad access for reaction screening and optimization.