N-Propylphthalimide-substituted bis-(NHC)PdX2 complexes: synthesis, characterization and catalytic activity in direct arylation reactions

Palladium-catalyzed direct arylation of heteroaromatics has become a popular method for producing carbon-carbon bonds via C-H bond activation. A wide diversity of heteroaromatics such as furan, thiophenes and thiazoles can be used for this reaction. This paper reports the synthesis of N-propylphthalimide-substituted bis-(NHC)PdX2 complexes (NHC = N-heterocyclic carbene), and their catalytic activity in direct arylation reactions. The complexes have been prepared from Ag(I)NHC precursors by transmetallation and characterized by spectroscopy and elemental analysis. The bis-(NHC)PdX2 complexes show excellent activity as catalysts in the direct arylation reactions of 2-n-butylfuran, 2-n-butylthiophene and 2-isopropylthiazole.