Sonogashira Reaction Catalyzed By Ionic Liquids

Sonogashira reaction is one kind of palladium-catalyzed cross-coupling reactions with Terminal Alkvnes. It is one of main methods which lead to the formation of C-C bond. used mainly in the synthesis of substituted alkenes and conjugated alkynes. This reaction provides an effective reaction route for the synthesis of aryl substituted polyacetylenes and their derivatives, which can be generally applied in the synthesis of nature products, bioactive molecules, nonlinear optical materials and polymer materials.Currently. the research on Sonogashira reaction is focused on two aspects:First, synthesize and screen the catalyst system which can be a very efficient catalyst for halogenated aromatics especially the aryl chlorides. Second, it can be applied to study the new synthetic methods of sonogashira reaction. The ionic liquid, as one of the most promising green solvents, therefore, the sonogashira reaction in ionic liquids has aroused people's attention extensively.In this paper, four amino-functionalized ionic liquids and five deep eutectic ionic liquids were prepared, the yields of products were over 80%.The products were characterized by IR spectra. UV spectra, NMR spectra, and TGA-DTA.The structures and physical properties such as density, melting points and solubility were characterized. The results showed that the two kinds of ionic liquids has good thermal stability and low melting point.The amino-functionalized ionic liquids were prepared by one-step process which is simple, easy and the yield and purity of the product were quite high, the product can be stable from room temperature to 250℃. The synthesis route of deep eutectic ionic liquids is moderate reaction, simple technology, easy source of other materials, the process can produce high quanlity of solvent with high selectivity and high yield.The two kinds of ionic liquids were applied respectively in Sonogashira reaction. The optimum reaction condition was obtained by the model reaction. The effect of the amount of catalyst, reaction temperature, reaction time and cycle index were studied. Then enlarged the application scope of reagent, the influence of ratio of reactant were studied. Experiment results showed that ionic liquids can be solvent and catalyst, which can be separated easily from reactants and reclaimed as well. After four repetitive cycling use, the yields of coupling product can also be 95%.