Aerobic Baeyer‐Villiger Oxidation Catalyzed by Metal Corroles

Abstract

Metal corrole catalyzed Baeyer-Villiger oxidation reaction was successfully achieved for the first time. Among all tested Co, Mn, Fe and Cu complexes of 5, 10, 15-Tris (pentafluorophenyl) corrole, Fe complex [Fe(tpfc)Cl] exhibited the best activity, and the highest yield was observed for six membered cyclic ketones. Preliminary results suggest that Fe(tpfc)Cl may act as an initiator for dehydrogenation of benzaldehyde to generate benzoyl radical, which will form peroxybenzoic acid under molecular oxygen atmosphere. The oxidation of Fe(tpfc)Cl catalyst by peroxybenzoic acid produces high-valent iron-oxo corrole intermediate. The iron-oxo corrole is attacked by cyclohexanone to form a Criegee adduct, which will finally generate ɛcaprolactone product to finish the catalytic cycle. The 4 A-MS additive may accelerate the production of perbenzoic acid and significantly improve the reaction yield.[a] M.

Enhanced Photoinduced Baeyer–Villiger Oxidation of Ketones by Introducing Trinuclear Ruthenium Clusters into Polyoxometalate-Based Metal–Organic Frameworks

“…The catalytic activity of CR-SiW 12 (catalyst dosage of 0.1 mol %, reaction time of 3 h, yield of 94.1%) was much higher than that of AcrH + ClO 4 – (catalyst dosage of 5 mol %, reaction time of 20 h, yield of 92%). Besides, compared with the conventional thermal-driven B–V oxidation of cyclohexanone (high temperature and pressure), our scheme has the advantages of mild reaction conditions, utilization of clean solar energy, high catalytic efficiency, and reusability, effectively reducing energy consumption, and avoiding the use of high-risk production equipment and other potential risks. − …”

“…Initially, CR-SiW 12 reaches its excited state [ CR-SiW 12 ]* under visible light (>400 nm) irradiation, then [ CR-SiW 12 ]* abstracts a hydrogen atom from benzaldehyde through the HAT process to generate C 6 H 5 CO • radical and H + [ CR-SiW 12 ] − . − The subsequent capture of O 2 by the C 6 H 5 CO • radical generates the C 6 H 5 COOO • radical. − Afterward, H + [ CR-SiW 12 ] − converts the C 6 H 5 COOO • radical to perbenzoic acid through the reverse HAT process and concurrently regenerates CR-SiW 12 back to the catalytic cycle . Finally, perbenzoic acid and cyclohexanone result in the formation of Criegee adduct intermediates, which undergo an intramolecular rearrangement to produce ε-caprolactone and benzoic acid. ,,, …”

“…In particular, the O 2 /aldehyde system known as the Mukaiyama method is very attractive in industrial production owing to its advantages of safety, green nonpollution, and high yield. , Recently, researchers have reported a lot of excellent work to develop a low-cost B–V oxidation process based on the Mukaiyama method. Nevertheless, conventional thermo-catalytic technologies often require high-temperature energy to trigger the catalytic reaction, which still suffers from the issues of high energy consumption and advanced facility requirements, thereby limiting the scalability of the process. − Recent studies show that photocatalytic technology has become a research hotspot in the field of organic synthesis by utilizing economical solar energy as the driving force, with advantages including mild reaction conditions, high selectivity, and environmental friendliness. − Consequently, the development of the photoinduced B–V oxidation process based on the Mukaiyama method is of great research significance.…”

“…5,6,11 As elucidated by EPR results, CR-SiW 70 Finally, perbenzoic acid and cyclohexanone result in the formation of Criegee adduct intermediates, which undergo an intramolecular rearrangement to produce ε-caprolactone and benzoic acid. 7,9,13,67 ■…”