Facile and Efficient Olefination of Aryl Halides Catalyzed by a Palladium Complex Containing a Heteroarene-Functionalized N-Heterocyclic Carbene

Abstract

[Ag4(L)4](PF6)4 and [Pd(L)2](PF6)2 (L = 3-(2,4-dimethyl-1,8-naphthyrid-7-yl)-1-picolylimidazolylidene) have been prepared and fully characterized. The silver compound consists of a Ag4 ring with short Ag−Ag contacts displaying a butterfly conformation. The palladium complex exhibits a helical structure with palladium located in a square-planar environment with two carbene ligands and two pyridines in a cis arrangement. The palladium complex has proven to be a highly efficient catalyst for Heck coupling reactions of aryl bromides with n-butyl acrylate. TON values up to 106 and TOF values up to 5 × 105 h−1 can be achieved.