Halo-Bridged Abnormal NHC Palladium(II) Dimer for Catalytic Dehydrogenative Cross-Coupling Reactions of Heteroarenes

This work describes the dehydrogenative coupling of heteroarenes using a dimeric halo-bridged palladium(II) catalyst bearing an abnormal NHC (aNHC) backbone. The catalyst can successfully activate the C-H bond of a wide range of heteroarenes, which include benzothiazole, benzoxazole, thiophene, furan, and N-methylbenzimidazole. Further, it exhibited good activity for heteroarenes bearing various functional groups such as CN, CHO, Me, OMe, OAc, and Cl. Additionally, we isolated the active catalyst by performing stoichiometric reaction and characterized it as the acetato-bridged dimer of (aNHC)PdOAc by single-crystal X-ray study.