Magnetite (Fe3O4) Nanoparticles-Catalyzed Sonogashira-Hagihara Reactions in Ethylene Glycol under Ligand-Free Conditions

A novel application of nanoparticles of paramagnetic magnetite (Fe3O4) as an efficient catalyst for carbon-carbon bond formation via the Sonogashira-Hagihara reaction under heterogeneous ligand-free conditions in ethylene glycol (EG) is described. By using this catalyst, arylalkynes are produced from the reaction of aryl iodides and activated heteroaryl bromides with alkynes. The results are reproducible using the catalyst, which was prepared from different sources. The catalyst is easily separated by an external magnetic field from the reaction mixture. The separated catalyst can be recycled for several consecutive runs without appreciable loss of its catalytic activity.