Microwave-assisted Sonogashira cross-coupling reaction catalyzed by CN-ortho-palladated complex of tribenzylamine under copper-free conditions

Abstract

The catalytic activity of [Pd{C6H4(CH2N(CH2Ph)2)} (µ-Br)]2 complex as an efficient, stable and non-sensitive to air and moisture catalyst was investigated in the Sonogashira cross-coupling reaction under microwave irradiation. In the presence of catalytic amount of this homogeneous catalytic system, various aryl halides were efficiently coupled with phenylacetylene under copper-free conditions. The substituted internal alkynes were produced in excellent yields in short reaction times in NMP at 100 °C. The combination of dimeric complex as homogenous catalyst and microwave irradiation and also NMP as microwave-active polar solvent gave higher yields in shorter reaction times.