Dewanji Abhishek, van Dalsen Leendert, Rossi-Ashton James A, Gasson Eloise, Crisenza Giacomo E M, Procter David J
Department of Chemistry, The University of Manchester, Manchester, UK.
Nat Chem. 2023 Jan;15(1):43-52. doi: 10.1038/s41557-022-01092-y. Epub 2022 Dec 5.
The photoactivation of electron donor-acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation of radical species. However, when it comes to aryl radical formation, this strategy remains hamstrung by the electronic properties of the aromatic radical precursors, and electron-deficient aryl halide acceptors are required. This has prevented the implementation of a general synthetic platform for aryl radical formation. Our study introduces triarylsulfonium salts as acceptors in photoactive electron donor-acceptor complexes, used in combination with catalytic amounts of newly designed amine donors. The sulfonium salt label renders inconsequential the electronic features of the aryl radical precursor and, more importantly, it is installed regioselectively in native aromatic compounds by C-H sulfenylation. Using this general, site-selective aromatic C-H functionalization approach, we developed metal-free protocols for the alkylation and cyanation of arenes, and showcased their application in both the synthesis and the late-stage modification of pharmaceuticals and agrochemicals.
电子供体-受体络合物的光活化已成为一种可持续、选择性且通用的产生自由基物种的策略。然而，在芳基自由基的形成方面，该策略仍受限于芳族自由基前体的电子性质，并且需要缺电子的芳基卤化物受体。这阻碍了用于芳基自由基形成的通用合成平台的实施。我们的研究引入了三芳基锍盐作为光活性电子供体-受体络合物中的受体，并与催化量的新设计的胺供体结合使用。锍盐标记使芳基自由基前体的电子特征变得无关紧要，更重要的是，它通过C-H亚磺酰化区域选择性地安装在天然芳香化合物中。使用这种通用的、位点选择性的芳香C-H官能化方法，我们开发了芳烃烷基化和氰化的无金属方案，并展示了它们在药物和农用化学品的合成及后期修饰中的应用。
