Amines As Ligands In The Copper-Catalyzed Cross-Coupling Reactions

Transition metals-catalyzed Sonogashira coupling reactions and N-arylation reaction have become important methods for the formation of the carbon-carbon bonds or carbon-nitrogen bonds, respectively. Recently, many kinds of catalysts and ligands have been developed for these reactions. However, the catalyst is usually palladium, which is expensive and can not be reusable. In addition, these transformations are often required ligands to improve them. But many of these ligands are expensive as well as are sensitive to water and air resulting in the reuse of these ligands difficultly. As a result, this dissertation is focused on the use of amines as ligands to improve Sonogashira cross-coupling and N-arylation reactions.1. Excellent results have been achieved in the Cu(OAc)₂-catalyzed Sonogashira cross-couplings of aryl iodides and activated bromides that utilize TBAF(tetra-n-butylammonium fluoride, n-Bu₄NF)as the base and 4,6-dimethoxypyrimidin-2-amine as the ligand. It is noteworthy that the reaction is conducted under aerobic, solvent-free and palladium-free conditions.2. Efficient and solvent-free copper-catalyzed N-arylations of imidazoles with aryl and heteroaryl halides have been demonstrated. In the presence of CuBr, 2-aminopyrimidine-4,6-diol and TBAF, a variety of imidazoles underwent the N-arylation reaction with aryl and heteroaryl halides smoothly in moderate to excellent yields.