Cu2O/Nano-CuFe2O4: An Efficient and Magnetically Recoverable Catalyst for the Ligand-free N-Arylation of Amines and Nitrogen Heterocycles with Aryl Halides

An efficient strategy has been developed for the N-arylation of azoles and aliphatic amines with aryl halide using a Cu2O/nano-CuFe2O4 magnetic composite as the catalyst and KOH as the base. The methodology is found to be applicable to a variety of nitrogen-containing heterocycles, such as imidazole, indole, and pyrrole, as well as aliphatic amines in high yields with practical simplicity under cost-effective "ligand-free" conditions. The magnetic property of the catalyst allowed its fast separation from the reaction medium by an external magnet. Additionally, the inexpensive catalyst could be recycled for five consecutive runs with small drops in catalytic activity.