Improved Copper-Catalyzed Cross Coupling Reactions And Their Applications In The One-pot Cascade Reaction For The Assembly Of Heterocyclic Compounds

The efficient C-X (X=N,O,S,Se,etc.) or C-C bond formation is one of the most important tasks in organic synthesis. Transition metal-catalyzed cross coupling reaction is a powerful protocol for the formation of C (sp, sp2 or sp3)-C and C-X (N, O, S, Se, etc.) bonds. This requires us to seek for some green, economic, efficient and versatile catalytic systems. The metals Pd and Ni catalyzed reactions usually proceeded well, but it have some intrinsic shortcomings (for example:toxic, higher prices, usually need unstable and highly toxic organic phosphine ligands, etc.), this has greatly impeded their large-scale application in organic synthesis. In recent years, copper catalyzed coupling reaction has made remarkable achievements, because of its low-cost, low toxicity, etc., the copper catalyzed coupling reaction has showed broad application prospects.In view of the advantages and application prospects, the copper catalyzed coupling reaction and optimization of the reaction condition were studied by our group. The dissertation includes five parts. The research development, current progress and trend of copper catalyzed coupling reactions were summarized in chapter one. In the second chapter, we studied the C-N bonds formation of copper (I)-catalyzed reaction under improved condition. In the third chapter, copper-catalyzed coupling reactions have been successfully applied to the assembly of various heterocyclic compounds via ligand-free one-pot strategies. In the forth chapter, we synthesis various of coumarin derivatives by the copper (Ⅰ)-catalyzed coupling reaction and the transition-metal-catalyzed C-C bond oxidative cleavage/re-formed reaction. The last chapter reported the iron-catalyzed "one pot" reaction in the synthesis of benzofuran derivatives under improved condition.The second chapter contains two sections. The first section is the synthesis of N-arylimidazole derivates by the catalyst of CuI/1,1’-binaphthyl-2,2’-diamine dihydrochloride (BINAM). Employing 1,1’-binaphthyl-2,2’-diamine (BINAM) dihydrochloride as an efficient and commercially available ligand, relatively mild and highly efficient copper-catalyzed coupling reaction of imidazole with aryl and heteroaryl halides have been developed. Various functional groups on the aryl halide could be tolerated. The second section is mainly in Cu2O-catalyzed Ullmann-Type reaction of vinyl bromides with imidazole and benzimidazole. We synthesized a series of N-vinylimidazoles under the mild CuI/β-keto ester catalyst system. The catalyst system needs less the amount of the catalyst, the reaction condition is mild, high yields and good stereoselectivity was also got. It has showed large industrial application prospects.Recently, copper-catalyzed coupling reactions have been successfully applied to the efficient assembly of various heterocyclic compounds via one-pot strategies. The third chapter contains three sections. These sections (part 1-3) are the application of copper-catalyzed coupling reactions in synthesis heterocyclic compounds via ligand-free one-pot protocols. We found that some useful heterocyclic compounds such as benzothiazole, benzoxazole, benzimidazole, benzoxazine derivatives could be facilely and efficiently synthesized from readily available materials.In the forth chapter, we studied the copper (Ⅰ)-catalyzed coupling reaction and the transition-metal-catalyzed C-C bond oxidative cleavage/re-formed reaction, various of heterocyclic coumarin derivatives were synthesized.In the fifth chapter, an iron-catalyzed procedure was employed to achieve both the Sonogashira cross-coupling and intramolecular O-arylation of o-iodophenols and aryl acetylenes or 1-aryl substituted-2-trimethylsilyl acetylenes. A variety of benzofurans were synthesized under the catalyst of FeCl3/1,10-phenanthroline. The catalyst system needs less the amount of FeCl3/1,10-phenanthroline and the yield is good.