NiCl2 center dot 6H(2)O: an efficient catalyst precursor for phosphine-free Heck and Sonogashira cross-coupling reactions

摘要

An efficient and simple protocol for the Heck reaction of aryl iodides and bromides using NiCl2 center dot 6H(2)O as the pre-catalyst is presented. The reactions proceed well in ethylene glycol in the absence of phosphine ligands and reducing agent. Compared to the frequently used expensive palladium catalysts, the use of nickel catalyst has an economic advantage and hence, remains attractive for large or industrial scale preparations. The efficient copper- and phosphine-free Sonogashira coupling reaction of aryl iodides is also demonstrated using this catalytic system. (c) 2015 Elsevier Ltd. All rights reserved.