Palladium(II)-N-Heterocyclic Carbene Complexes: Efficient Catalysts for the Direct C-H Bond Arylation of Furans with Aryl Halides

This paper contains the synthesis and characterization of the seven new benzimidazolium salts and their corresponding new palladium(II)-NHC complexes with the general formula [PdX2(NHC)(2)], (NHC=N-heterocyclic carbene, X=Cl or Br), and also their catalytic activity in direct C-H bond arylation of 2-substituted furan derivatives with aryl bromides and aryl chlorides. Under the optimal conditions, these palladium(II)-NHC complexes showed the good catalytic performance for the direct C-H bond arylation of 2-substituted furans with (hetero)aryl bromides, and with readily available and inexpensive aryl chlorides. The C-H bond arylation regioselectively produced C5-arylated furans by using 1mol% of the palladium(II)-NHC catalysts in moderate to high yields.