Metal-Organic Framework-Organocatalyst Combination as Powerful Biomimetic Multi-Catalytic Systems for Aerobic Oxidations

Aerobic oxidation using molecular oxygen as terminal oxidant represents a sustainable route to access valuable organic compounds. However, achieving high selectivity in such transformations remains challenging. Here, we report a robust and modular biomimetic multicatalytic system combining a MOF and a simple hydroxyaromatic co-catalyst, which mimics the cooperative action of enzyme–coenzyme pairs in a confined environment. A Zr-based (MOF-808) semiheterogeneous system enables the selective aerobic oxidation of anilines to azoxybenzenes, products that are typically elusive under aerobic conditions, with excellent yields and selectivity, reaching up to 93%. The cooperative interplay between MOF and organic co-catalyst triggers ligand-to-metal charge transfer, generating reactive oxygen species under mild conditions without the need for light or other external stimuli. The generality of this novel approach is further demonstrated by applying it to a Ti-MOF (MIL-125) to achieve aerobic oxidative coupling of benzylamines. This work highlights the untapped potential of MOF-organocatalyst combinations to drive challenging reactions under environmentally benign conditions.