Bis(pyrazolyl)methane Copper Complexes as Robust and Efficient Catalysts for Sonogashira Couplings

Abstract

Abstract A series of bis(pyrazolyl)methane copper complexes were found to catalyze a fast palladium‐free Sonogashira coupling reaction of several iodoarenes with terminal alkynes such as phenylacetylene, propargyl benzyl ether, and ( tert ‐butyl‐dimethyl)silylacetylene. These reactions proceed with CuCl 2 · 2H 2 O (10 mol‐%) under aerobic conditions and the corresponding chelate ligand (10 mol‐%), with its tailored facial coordination mode, is crucial for the success of the reaction. The coupling can also be carried out in water with liquid aryl halides and a phase‐transfer catalyst.