Rh(?)-catalyzed Bis-cyanation Of Imidazo[1,2-?]pyridines

This thesis studied bis-cyanation of imidazo[1,2-?]pyridine catalyzed via an efficient Cp*Rh(?)catalyst.Under the optimized conditions,a broad rang of imidazo[1,2-?]pyridine derivatives proceeded smoothly to afford the corresponding cyanation products using N-cyano-N-phenyl-p-methylbenzene-sulfonamide as the CN source,[Rh Cp*Cl2]2 and Ag Sb F6 as the catalyst and Na HCO3 as the base.Also,the plausible reaction mechanism has been proposed.The main results were listed as follows: 1.Synthesis of imidazo[1,2-?]pyridines.Imidazo[1,2-?]pyridines were synthesized via employment of 2-aminopyridines and acetophenones as the starting materials,copper acetate and zinc iodide as the catalyst,and 1,10-phenanthroline as the ligand using ortho-dichloro-benzene as the solvent.2.Bis-cyanation of imidazo[1,2-?]pyridines in Cp*Rh(?)catalytic system.2-Phenylimidazo[1,2-?]pyridine and NCTS were used as the model subustrates to optimize the bis-cyanation reaction conditions.In a 35 m L vial were combined 2-Phenylimidazo[1,2-?]pyridines(0.1 mmol),NCTS(0.25 mmol),[Rh Cp*Cl2]2(0.005 mmol),Ag Sb F6(0.04 mmol),and Na HCO3(0.05 mmol)in DCE(1 m L).The reaction vial was sealed and heated to 120 °C for 24 h.After cooling to room temperature,the product was isolated to afford the desired product in 89% yield.Afterwards,various bis-cyanation of imidazo[1,2-?]pyridine substrates were carried out under the optimized conditions to generate the desired products in high yields with broad functional group tolerance(Scheme 1).Furthermore,a gram-scale preparation of bis-cyanated products was also performed.Finally,the plausible reaction mechanism was proposed through the H-D exchange experiment and the isotope effect experiment.