Moderately Oxidizing Thioxanthylium Organophotoredox Catalysts for Radical-Cation Diels–Alder Reactions
Kenta Tanaka, Mami Kishimoto, Yuta Tanaka, Yusuke Kamiyama, Y. Asada, Mayumi Sukekawa, Naoya Ohtsuka, Toshiyasu Suzuki, Norie Momiyama, Kiyoshi Honda, Yujiro Hoshino
Abstract
Moderately oxidizing thioxanthylium photoredox catalysts that operate under irradiation with green light have been developed. These catalysts exhibit relatively moderate excited-state reduction potentials [E1/2(C*/C•–) = 1.75–1.94 V vs saturated calomel electrode (SCE)] and can efficiently promote radical-cation Diels–Alder reactions under irradiation with green light. Interestingly, β-halogenostyrenes (Ep/2 = 1.57–1.61 V vs SCE) are well tolerated, affording synthetically useful halocyclohexenes.
Topics & Concepts
Oxidizing agentCatalysisChemistrySaturated calomel electrodePhotochemistryIrradiationExcited stateRadical ionElectrochemistryOrganic chemistryElectrodeIonWorking electrodePhysical chemistryNuclear physicsPhysicsRadical Photochemical ReactionsSulfur-Based Synthesis TechniquesOxidative Organic Chemistry Reactions