Sonogashira Coupling Reaction Of Aryl Iodides With Terminal Acetylenes In Ionic Liquid

The Sonogashira coupling reaction ( palladium-copper catalyzed reaction of terminal alkynes with aryl or vinyl halides) is one of the most important and widely used C-C bond formation reactions in organic synthesis. The Sonogashira reaction is generally carried out in organic solvents such as benzene, toluene, dioxane, THF or DMF, and catalyzed by palladium compound with copper salts used as cocatalysts. However, the copper salts can also induce Glaser-type homocoupling of the alkynes. In the meantime, the separation of the products from the reaction mixture, the recovery of the expensive palladium catalysts, and the need for organic solvents are the major disadvantages in the catalytic process.The room temperature ionic liquid is a new type of solvent that present interesting properties such as wide liquid range, good thermal and chemical stability, negligible vapor pressure, and the potential for recycling, and many reactions can be carried out in ionic liquid.We have researched on the synthesis of phosphine ligand and ionic liquid, and the Sonogashira reaction in ionic liquid. The main results are as follows:1. Synthesis of ionic liquid [BMIm][PF6] and 1,1'-bis(diphenylphosphino) Cobaltocenium hexafluorophosphate.2. The influene of phosphine ligand, base, reaction temperature on the Sonogashira reaction was studied and found out the best condition for Sonogashira reaction of iodobenzene with phenylacetylene.3. The Sonogashira reaction of the various aryl iodides with several terminal acetylenes.4. The recyclability of the Sonogashira reaction of iodobenzene with phenylacetylene under PdCl₂/dppc⁺PF₆^-/[BMIm][PF₆] catalytic system.