Ni(acac)2/2,6-bis(diphenylphosphino)pyridine/CuI: A highly efficient palladium-free homogeneous catalyst for the Sonogashira cross-coupling reaction

Abstract

A highly efficient palladium-free homogeneous catalyst involving Ni(acac)2/2,6-bis(diphenylphosphino)pyridine ((Ph2P)2py)/CuI components was used for the Sonogashira cross-coupling reaction. The Sonogashira reaction was investigated between phenylacetylene and various bromo- and chloroarenes containing electron-neutral, electron-rich, electron-poor, electron-deficient, and sterically hindered aryl fragments. The aryl alkynes coupling products were obtained with good to excellent yields at the optimized conditions using Ni(acac)2 (0.3 mol%)/(Ph2P)2py (0.6 mol%)/CuI (0.03 mol%) as the catalyst, tetrabutylammonium bromide (TBAB) as the additive, Et3N as the base in DMF at 100 °C under N2 atmosphere.