Due to many vast application of C-C bond formation in the areas including bioactive compounds, natural products and high performance materials, over the past few years, the C-C coupling reactions have become a versatile tool in organic synthesis. One of the most efficient methods in this category is Sonogashira coupling reaction. In this work the application of a new, efficient and inexpensive ionic liquid; copper(I) chlorid /Cholin chlorid is studied.
The ionic liquid; catalytic system has been developed to catalyze ligand and palladium-free Sonogashira coupling reactions of phenylacetylenes with a variety of aryl halides to afford the corresponding coupling products in 18-97% yields. The present catalytic system appears attractive in view of its ease of application and low cost, due to the use of a readily available non-noble metal catalyst combined with the absence of ligands. We found that electron-withdrawing and donating substituents on aryl halides enhanced the coupling of aryl halides with phenyl acetylenes. Excellent yield of the Sonogashira reaction catalyzed by 20 mol% ionic liquid could be achieved at 140 °C and DMF as the solvent within 2-10 hours.