Research On Heck Cross-Coupling Reaction Catalized By Pd Or Cu Compounds In Water

Heck cross-coupling reaction is an important method for the synthesis ofcarbon-carbon bonds, and greatly attracted more people’s attention for its widelyapplication in the dye, medicine, natural products, pesticides, perfumes, cinnamic acidderivatives and the preparation of new polymer materials. The traditional Heckcoupling reaction requires a palladium catalyst with a ligand, and performs in anorganic solvent. Water, non-toxic, nonflammable, green, cheap and easy to get, etc., isan ideal alternative to organic solvents. This dissertation reports the four catalystsystems suitable for the Heck coupling reaction in water medium, without thepresentation of the phosphine ligand.A series of Salicylidene imine Schiff base ligand was synthesized by substitutedphenol and were tested for Heck coupling reaction in aqueous. And the reactionconditions were optimized. Catalyzed by the selected catalytic system, under theoptimum conditions, the aryl bromides and aryl chlorides activated by electronwithdrawing groups can smoothly coupled with n-butyl acrylate and styrene andobtained the products with60-97%yields. The organic solvent is not involved in thereaction system and the post-treatment is simple.Some Betti bases were prepared by the Mannich reaction through2-pyridinecarboxaldehyde, β-naphthol and amine. The effect of Betti base as ligand forthe Heck coupling reaction in water was invested, and the ligand1-((4-morpholinyl)(2-pyridyl)methyl)-2-naphthol was the most efficient for thereaction. The aryl iodides, and aryl bromides and activated aryl chlorides withelectron withdrawing groups can successful couple with vinyl compounds. With wateras solvent, the reaction conditions are relatively mild and applied for wide range ofsubstrates. In addition, when in DMF, the ligand can promote copper-catalyzed Heckcoupling reaction successfully.A series of diimine ligands were synthesized, and these ligands as co-catalystwere tested for Heck coupling in water. With palladium as catalyst in the reaction, thearyl iodides, aryl bromides and activated aryl chlorides with electron withdrawinggroups had high reactivity, the coupling product could be obtained in a high yield.While with CuI as catalyst, the aryl iodides, and aryl bromides could also couple withn-butyl acrylate smoothly, but the activited aryl chlorides couldn’t react well. Thepreparation of the ligands was simple, and with water as solvent, reaction conditions were mild without inert gas protection, the scope of the substrate is relatively wide.Ligand-free CuI/TBAB catalytic system with NaOH as a base has beendevoleped for Heck reaction in water. Different substituted aryl iodides, aryl bromidesreacted with n-butyl acrylate and styrene very smoothly and afforded thecorresponding products with yields of61-95%. The ligand-free copper as a catalyst ischeaper, and the catalyst can be reused. The reaction conditions are mild in water, andthe scope of the substrate is relatively broad.