Zhou Wei, Wu Shuo, Melchiorre Paolo
ICIQ─Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Països Catalans 16, 43007 Tarragona, Spain.
Department of Analytical Chemistry and Organic Chemistry, University Rovira i Virgili, 43007 Tarragona, Spain.
J Am Chem Soc. 2022 May 25;144(20):8914-8919. doi: 10.1021/jacs.2c03546. Epub 2022 May 13.
Excitation of photoactive electron donor-acceptor (EDA) complexes is an effective way to generate radicals. Applications in a catalytic regime typically use catalytic donors. Herein, we report that readily available electron-poor tetrachlorophthalimides can act as effective organocatalytic acceptors to trigger the formation of EDA complexes with a variety of radical precursors not amenable to previous catalytic methods. Excitation with visible light generates carbon radicals under mild conditions. The versatility of this EDA complex catalytic platform allowed us to develop mechanistically distinct radical reactions, including in combination with a cobalt-based catalytic system. Quantum yield measurements established that a closed catalytic cycle is operational, which hints at the ability of tetrachlorophthalimides to readily turn over and govern each catalytic cycle.
光活性电子供体-受体（EDA）配合物的激发是产生自由基的有效方法。在催化体系中的应用通常使用催化供体。在此，我们报道了易于获得的缺电子四氯邻苯二甲酰亚胺可以作为有效的有机催化受体，以引发与多种自由基前体形成EDA配合物，而这些自由基前体不适用于先前的催化方法。可见光激发在温和条件下产生碳自由基。这个EDA配合物催化平台的多功能性使我们能够开发出机理不同的自由基反应，包括与钴基催化体系结合。量子产率测量表明一个封闭的催化循环是可行的，这暗示了四氯邻苯二甲酰亚胺易于周转并控制每个催化循环的能力。
