Cu(0)@Al2O3/SiO2 NPs: An efficient reusable catalyst for the cross coupling reactions of aryl chlorides with amines and anilines

Article abstract of DOI:10.1039/c5ra19337k

The C-N cross coupling reaction of aryl chlorides with various alkyl/aryl amines catalyzed by copper nanoparticles impregnated on alumina/silica support (Cu(0)@Al₂O₃/SiO₂) was investigated. The prepared catalyst was characterized for its intrinsic physico-chemical and textural properties using XRD, XPS, HR-TEM, BET surface area, SEM-EDAX, H₂-TPR and ICP-AES techniques. The catalyst exhibits excellent reactivity and efficacy in the cross-coupling of a wide range of alkyl/aryl amines including challenging anilines with aryl chlorides. The catalyst offers significant advantages such as brevity, milder reaction conditions, excellent yields and high functional group tolerance for C-N cross coupling when compared with the other reported methods. Moreover, this atom-economical methodology does not require an additional ligand or co-catalyst/activator. The Cu(0)@Al₂O₃/SiO₂ catalyst was efficiently applied to a gram scale synthesis of 7-chloro-4-(4-(2-nitrophenyl)piperazin-1-yl)quinolone (2k). The robustness of the catalyst was examined by reusing it for five consecutive runs.