Europium‐Catalyzed Aerobic Oxidation of Alcohols to Aldehydes/Ketones and Photoluminescence Tracking

Europium is a lanthanide rare‐earth metal and is known as a key element in luminophore development. Since europium has two relatively stable oxidation states, Eu2+ and Eu3+, which is exceptional among the various lanthanide elements, we have developed a europium‐catalyzed aerobic oxidation with external oxidants utilizing the redox cycle of Eu2+/Eu3+. The reaction was performed under mild conditions with a wide substrate scope. The photoluminescence spectra clearly demonstrate the oxidation state changes that occur during the presented europium‐catalyzed aerobic oxidation.