•The catalytic activity of a series of heteroaryl coordinated chelating NHC palladium complexes towards the phosphorylation of coumarins was presented.•The chelating NHC palladium complex bearing the most σ-donating backbone and a more rigid five-membered chelating ring showed the highest efficiency.•Optimized conditions: AgNO3 as oxidant, CH3CN as solvent, 80 °C.•The system showed high catalytic activity and wide functional group tolerance.The catalytic activity of a series of heteroaryl coordinated chelating N-heterocyclic carbene (NHC) palladium complexes bearing different N-substituents, NHC backbones and chelating rings towards the phosphorylation of coumarins, and the relationship between the activity and the structure are presented. The results showed that the chelating NHC palladium complex Ia–b bearing the most σ-donating backbone and a more rigid five-membered chelating ring showed the highest efficiency. Using AgNO3 as oxidant, a wide range of coumarins reacted with different dialkyl phosphite or diphenylphosphine oxide smoothly in CH3CN, producing the target product in moderate to high yields.The catalytic activity of a series of heteroaryl coordinated chelating N-heterocyclic carbene (NHC) palladium complexes bearing different N-substituents, NHC backbones and chelating rings towards the phosphorylation of coumarins, and the relationship between the activity and the structure are presented.

The synthesis of novel pincer palladium complexes containing ring expanded six-membered N-heterocyclic carbenes (NHCs) via direct metallation of the precursors tetrahydropyrimidin-1-ium hexafluorophosphates in the presence of NaN(SiMe3)2 is presented. The structure has been characterized unambiguously by X-ray single crystal analysis. Catalytic activity investigation showed that the complexes catalyzed the Heck reaction of aryl bromides with acrylate/styrene efficiently when using Et3N as base and DMA as solvent.

The synthesis of novel chelating palladium complexes containing pyridine/pyrimidine hydroxyalkyl di-functionalized N-heterocyclic carbenes (NHCs) via direct metallation of the precursor imidazolium salts is presented. The structure has been characterized unambiguously by X-ray single crystal analysis. Catalytic activity investigation showed that the complexes catalyse the direct C–H bond arylation of (benzo)oxazoles efficiently when using tBuOLi as base and DMF as solvent.