Zinc-bis(imino)pyridine Complexes as Catalysts for Intermolecular Amidation of Benzylic C(sp3)−HBond

Abstract

Efficient NNN-pincer type bis(imino)pyridine ligand based zinc(II) catalyzed intermolecular amidation of benzylic hydrocarbons with sulfonamides has been developed. The zinc complexes were synthesized by the reaction of bis(imino)pyridine ligand with zinc(II) precursors such as Zn(OAc)2 ⋅ 2H2Oand ZnBr2. The structure of the bis(imino)pyridine-Zn(OAc)2 complex was characterized by single crystal X-ray diffraction. The zinc(II)-bis(imino)pyridine complexes were utilized as catalysts for the intermolecular amidation of benzylic C(sp3)−H bond in the presence of N-bromosuccinimide (NBS) as an oxidant. A broad range of substrates delivered the products in moderate to good yields. This protocol provides the synthesis of various amides viaC−H activation.