Consecutive Oxidation/Condensation/Cyclization/Aromatization Sequences Catalyzed by Nanostructured Iron(III)-Porphyrin Complex towards Benzoxazole Derivatives

A facile, efficient, and eco-friendly strategy to access benzoxazole heterocyclic products has been accomplished through oxidation of catechols followed by condensation/cyclization/aromatization sequences. This process is catalyzed by nanostructured iron(III)-porphyrin complex to form desired benzoxazole derivatives at room temperature under air condition. The procedure is widely applicable to diverse amines, and can provide the heterocyclic products in a scalable fashion, as well. One of the most significant types of oxidizing agents in nature is the iron-porphyrin complexes (0.1 mol-%), existing in the structure of hemoglobin. They have benefits such as low toxicity and high oxidation potential for many substrates.