Weakly ligated palladium complexes PdCl2(RCN)2 in piperidine: versatile catalysts for Sonogashira reaction of vinyl chlorides at room temperature

Copper iodide and weakly ligated palladium complexes PdCl2(RCN)2 (R=Ph, Me) catalyzed efficiently the coupling reaction of vinyl chlorides with 1-alkynes in the presence of piperidine to give the corresponding conjugated enynes in good to excellent yields. The reaction takes place rapidly and cleanly at room temperature. Application to the synthesis of terbinafine which exhibits strong antimycotic activity has been realized.