Carbon-Carbon And Carbon-Nitrogen Cross Coupling Reactions Catalyzed By Copper-based Materials

C?C and C?N bonds formation catalyzed by transition-metal complexes have received considerable attention in the past decades. Pd, Pt, Ni and Cu are all the good catalysts for these reactions. In comparison with others, copper-based materials are cheaper catalysts with lower toxicity. Not only do copper catalyst help reduce the cost but it also make the environmental pollution down. In this paper we wish to report our work about the cross-coupling reactions of amides with aryl halides and the homo-coupling reactions of terminal alkynes catalyzed by Copper-based materials. We want to give our efforts to this methodology.1. The cross coupling reaction of amides with aryl halides catalyzed by Cu2O nanoparticles were investigated. Using the coupling of 4-iodoanisole with benzamide as the model reaction, we explored the optimized reaction condition after screening various solvents, bases and ligands. The optimized reaction condition is: 0.05 eq Cu₂O, 0.10 eq N, N'-dimethylethylenediamine, 1.5 eq K₃PO₄·3H₂O, toluene, 110°C. Then several aryl iodides and aryl bromides were employed under the condition and most of them gave the moderate to excellent yields. No spectacular electronic effects were observed when benzamide was submitted to coupling with electron-rich and electron-poor substituted aryl halides, however, steric effects were more significant, para-substituted aryl halides gave higher yields obviously than ortho-substituted ones did. We also found that less reactive aryl chlorides gave moderate to good yields at 130°C. No loss of the catalytic activity was observed even after 5 runs. In comparison with homogeneous solution conditions, heterogeneous catalysis can facilitate the catalyst separation, simplify catalyst recovery and recycling, avoid the waste of catalysts, and eventually be prospective to accord with the aim of green chemistry. The proposed mechanism for the coupling reaction catalyzed by Cu₂O nanoparticles may be through a coordination-recyclable process via oxidative addition followed by reductive elimination. All products were characterized by ¹H NMR,¹³C NMR,IR and HRMS.2. The homo-coupling reaction of terminal alkynes catalyzed by CuSO4 was studied. The reaction have been accomplished smoothly in the presence of 0.05 eq CuSO₄·5H₂O and 1.50 eq NaOAc·2H₂O in DMF, and we found that aromatic alkynes gave higher yields than alphatic alkynes. This method use the more simple catalyst and the ligand free condition, but heterocyclic aromatic alkyne gave poor results.