Oxidase Catalysis via Aerobically Generated Hypervalent Iodine Intermediates

2017-09-20T17:22:31Z (GMT) by Asim Maity Sung-Min Hyun David Powers
Development of sustainable oxidation chemistry demands strategies to harness O<sub>2</sub> as a terminal oxidant. In particular, oxidase catalysis, in which O<sub>2</sub> serves as a chemical oxidant without necessitating oxygen incorporation into reaction products, would allow diverse substrate functionalization chemistry to be coupled to O<sub>2</sub> reduction. Direct O<sub>2</sub> utilization must overcome the intrinsic challenges imposed by the triplet ground state of O<sub>2</sub> and the disparate electron inventories of four-electron O<sub>2</sub> reduction and two-electron substrate oxidation. Here, we generate hypervalent iodine reagents, a broadly useful class of selective two-electron oxidants, from O<sub>2</sub>. Synthesis of these oxidants is achieved by intercepting reactive intermediates of aldehyde autoxidation. The use of aryl iodides as mediators of aerobic oxidation underpins an oxidase catalysis platform that couples a broad array of substrate oxidations to O<sub>2</sub> reduction, including olefin functionalization chemistry, carbonyl a-oxidation, oxidative dearomatization, and aerobic C–H amination chemistry.