Tetrakis(acetonitrile)copper(I) hexafluorophosphate (Cu(CH3CN)4PF6) is used as an efficient catalyst in the Pechmann condensation reaction of phenols with ethyl acetoacetate leading to the formation of coumarin derivatives in excellent yields under solvent free conditions at ambient temperature. The method is simple, solvent-free and gives excellent yields in a short reaction time.
