A Robust Magnetically Recoverable Nickel Nanocatalyst for Sustainable α-Olefination of Nitriles Using Primary Alcohols

A novel nickel nanocatalyst with a magnetic core was designed and synthesized through a multi-step procedure. First, an iron oxide core was synthesized (Fe ₃ O ₄ ), then coated with a silica layer (Fe ₃ O ₄ @SiO ₂ ). The catalyst support was further functionalized using epichlorohydrin (EP) and ortho -phenylenediamine (OPDA) (Fe ₃ O ₄ @SiO ₂ /EP/OPDA), and finally, nickel was loaded onto the structure to obtain the finished catalyst (Fe ₃ O ₄ @SiO ₂ /EP/OPDA@Ni). Its successful fabrication was confirmed by various characterization techniques, including X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating-sample magnetometry. The nanocatalyst was then effectively applied in the α-olefination of nitriles using primary alcohols through the reaction of a benzyl alcohol derivative with a benzyl cyanide derivative in refluxing toluene, using KO t -Bu as the base. The catalyst could be easily separated from the reaction mixture by applying an external magnetic field. It was also reusable, retaining its activity with only a minor loss over at least five consecutive cycles.