Choline chloride/CuCl as an effective homogeneous catalyst for palladium-free Sonogashira cross-coupling reactions

Choline chloride–CuCl (ChCl–CuCl) has been employed as an efficient catalytic system in the palladium-free Sonogashira-type cross-coupling reactions of phenylacetylene with a variety of aryl halides. Choline chloride, as an effective ligand and a quaternary ammonium salt, demonstrated an efficient stabilizing effect on the Cu(I) species during the reaction. This homogeneous catalytic system is attractive in view of its ease of application and low cost.