Easy copper-, ligand- and amine-free sonogashira coupling reaction catalyzed by palladium on carbon at low catalyst loading and by exposure to air

An easy copper-, ligand and amine-free Sonogashira coupling reaction catalyzed by commercially available palladium on carbon with air at low catalyst loading (0.2 mol% Pd) has been developed. Aryl iodides coupled with aromatic alkynes gave good to excellent yields and with aliphatic alkyne gave moderate to good yields. The reaction system is easy to handle.