Cui Ullmann Coupling Of Catalytic Reaction And Its Application In Synthesis Of Heterocyclic Compounds

The copper-catalyzed cross-coupling reactions to form sp2C-C or C-hetero atom bonds are very valuable transformations for organic synthesis, had received considerable attention in the past decades. In this dissertation we report our recent investigations on the cross-coupling reactions of aryl halides with hydrazide under the catalysis of Cul and amino acids at relatively low temperature. Applications of these newly developed reactions to nitrogen-atom-containing compounds preparation are also presented.In the chapter2of this dissertation, by combination the ortho-substituent and ligand effects, we performed the coupling reaction of2-bromotrifluoroacetylaniline and N-acy1hydrazine catalyzed by CuI under room temperature, which undergo in situ additive cyclization under acidic conditions to give substituted1H-benzimidazole-l-amine in excellent yield. Both electron-rich and electron-poor aryl halides could react with hydrazides to give the corresponding products in good to excellent yields. However, the coupling reaction of other2-iodoacetanilide with N-Boc hydrazide needed reaction temperature about40℃to ensure complete conversion. The reaction products are further converted into1H-benzimidazole-l-amine in moderate yield, upon treatment with10%HC1at80℃. The iodides contain aliphatic and aromatic amido groups coupled with N-acyl hydrazide would take place at room temperature with useless of ligand, affording the double coupling product in good to excellent yield.In the chapter3of this dissertation, we discoved the copper-catalyzed coupling of N-acyl-N’-substituted hydrazines with aryl iodides took place at60-90℃to provide N-acyl-N,N’-disubstituted hydrazines regioselectively. A number of functional groups are tolerated under these reaction conditions, providing these azo compounds with good diversity. We also developed a facial and effective method for assembly of1-aryl-1H-indazoles via CuI/4-OH-L-proline-catalyzed amination of2-bromoarylcarbonylic compounds. Owing to strong ortho-substitutent effect directed by acyl group, the coupling reaction occurred at60-125℃to provide amination products, which delivered1-aryl-1H-indazoles upon treatment which acetic acid at60℃. This method allows the assembly of a wide range of polysubstituted indazoles because variration at the1-and3-positions of the indazole is possible by employing differentt hydrazides and varying the acyl groups of the2-bromoarylcarbonylic. At last, we revealed a convenient approach for assembly of1-aryl indoles. This conversion involves a Cul catalyzed coupling between N-acyl-N-disubstituted hydrazines and iodides, followed by an in situ hydrolysis/Fischer cyclization protocol. Variations at the1-,2-, and3-positions of the indoles were achieved by employing the corresponding keto and N-aryl hydrazides.