A General Light-Driven Organocatalytic Platform for the Activation of Inert Substrates |
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| Authors: | Shuo Wu Florian Schiel Prof. Dr. Paolo Melchiorre |
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| Affiliation: | 1. ICIQ—Institute of Chemical Research of Catalonia, the Barcelona Institute of Science and Technology, Avenida Països Catalans 16, 43007 Tarragona, Spain These authors contributed equally to this work.;2. University of Bologna, Department of Industrial Chemistry ‘Toso Montanari', via Piero Gobetti 85, 40129 Bologna, Italy |
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| Abstract: | Due to their strong covalent bonds and low reduction potentials, activating inert substrates is challenging. Recent advances in photoredox catalysis offered a number of solutions, each of which useful for activating specific inert bonds. Developing a general catalytic platform that can consistently target a broad range of inert substrates would be synthetically useful. Herein, we report a readily available indole thiolate organocatalyst that, upon excitation with 405 nm light, acquires a strongly reducing power. This excited-state reactivity served to activate, by single-electron reduction, strong C−F, C−Cl, and C−O bonds in both aromatic and aliphatic substrates. This catalytic platform was versatile enough to promote the reduction of generally recalcitrant electron-rich substrates (Ered<−3.0 V vs SCE), including arenes that afforded 1,4-cyclohexadienes. The protocol was also useful for the borylation and phosphorylation of inert substrates with a high functional group tolerance. Mechanistic studies identified an excited-state thiolate anion as responsible of the highly reducing reactivity. |
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| Keywords: | Radical Chemistry Organocatalysis Photocatalysis Reaction Mechanisms Reductions |
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