Copper-free Sonogashira coupling in amine–water solvent mixtures

Extensive study of different amine–water solvent mixtures was carried out for copper free Sonogashira coupling of aryl iodides. The influence of the palladium sources, ligands, amine–water ratio and further additives was also evaluated. Application of sec-butylamine–water mixture proved to be an excellent medium for rapid and efficient coupling of aryl-iodides at ambient temperature in the presence of PdCl2(PPh3)2 as catalyst.