Recyclable Magnetic Nanoparticle-Supported Iodoarene Catalysts for Oxidation of 4-Alkoxyphenols to Quinones

Iodoarene catalysts immobilized on magnetite (Fe₃O₄) were developed. The reactivity of catalysts 4a and 4b were similar to that of 4-iodophenoxyacetic acid (3) for the oxidation of 4-alkoxyphenols in the presence of Oxone^® as a co-oxidant to give the corresponding p-quinones in high yields. In addition, 4b was readily recovered by the use of an external magnet and was recycled up to eight times. This is the first example of a magnetic, nanoparticle-supported iodoarene catalyst. Drawn to it like a magnet: The reactivity of iodoarene catalysts immobilized on magnetite (Fe₃O₄) were similar to that of 4-iodophenoxyacetic acid for the oxidation of 4-alkoxyphenols in the presence of Oxone^® as a co-oxidant to give the corresponding p-quinones in high yields. These catalysts were readily recovered by the use of an external magnet and were recycled up to eight times.