Synthesis of N-heterocyclic carbene-Pd(II) complexes and their catalytic activity in the Buchwald-Hartwig amination of aryl chlorides

Novel N-heterocyclic carbene-palladium(II) complexes using 2-picolinic acid as the ancillary ligand have been successfully developed under mild conditions. Their catalytic activity in organic synthesis has been initially tested in the Buchwald-Hartwig amination of secondary and primary amines with aryl chlorides. Various substituents on both substrates can be tolerated, giving the desired coupling products in good to almost quantitative yields. The minimum catalyst loading can be 0.01 mol%, implying their potential application toward industrial processes. (C) 2017 Elsevier Ltd. All rights reserved.