Recyclable and reusable NiCl₂(PPh₃)₂/CuI/PEG‐400/H₂O system for the sonogashira coupling reaction of aryl iodides with alkynes

Abstract

A stable and highly efficient NiCl2(PPh 3 ) 2 /CuI/PEG‐400/H 2 O catalytic system for the Sonogashira reaction has been developed. In the presence of NiCl 2 (PPh 3 ) 2 and CuI, the coupling reaction of aryl iodides with terminal alkynes was carried out smoothly in a mixture of poly(ethylene glycol) (PEG‐400) and water at 100°C with K 2 CO 3 as base to afford a variety of arylacetylenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether, and the NiCl 2 (PPh 3 ) 2 /CuI/PEG‐400/H 2 O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile organic solvents but also solves the basic problem of catalyst reuse. Copyright © 2015 John Wiley & Sons, Ltd.