NHC-Pd Complex-Catalyzed Double Carbonylation of Aryl Iodides with Secondary Amines to α-Keto Amides.

A series of palladium–NHC compounds were prepared and their catalytic activity in the double carbonylation of aryl iodides to synthesize α-keto amides were examined. Palladium complexes bearing mixed NHC–phosphine exhibited high efficiency for the double carbonylation reaction. The effects of different solvents, base, temperature, carbon monoxide (CO), pressure, various amine and aryl iodides were investigated. Both electron-rich and electron-deficient aryl iodides afforded the corresponding substituted α-keto amides in moderate to good yields. A possible mechanism was also proposed.