Department of Chemical Sciences , Indian Institute of Science Education and Research-Kolkata , Mohanpur - 741246 , India.
J Am Chem Soc. 2018 Jul 5;140(26):8330-8339. doi: 10.1021/jacs.8b04786. Epub 2018 Jun 22.
In recent years, merging different types of catalysis in a single pot has drawn considerable attention and these catalytic processes have mainly relied upon metals. However, development of a completely metal free approach integrating organic redox and organic Lewis acidic property into a single system has been missing in the current literature. This study establishes that a redox active phenalenyl cation can activate one of the substrates by single electron transfer process while the same can activate the other substrate by a donor-acceptor type interaction using its Lewis acidity. This approach has successfully achieved light and metal-free catalytic C-H functionalization of unactivated arenes at ambient temperature (39 entries, including core moiety of a top-selling molecule boscalid), an economically attractive alternative to the rare metal-based multicatalysts process. A tandem approach involving trapping of reaction intermediates, spectroscopy along with density functional theory calculations unravels the dual role of phenalenyl cation.
近年来，将不同类型的催化反应在一个容器中进行合并引起了广泛关注，这些催化过程主要依赖于金属。然而，在当前文献中，将有机氧化还原和有机路易斯酸性性质整合到单一体系中而完全不使用金属的方法尚未得到发展。本研究表明，氧化还原活性的菲咯啉阳离子可以通过单电子转移过程激活其中一种底物，同时可以通过路易斯酸性的供体-受体相互作用激活另一种底物。这种方法成功地实现了在室温下（39 个条目，包括畅销分子 boscalid 的核心部分）对未活化芳环的光和无金属催化 C-H 官能化，这是一种有吸引力的替代稀有金属多催化剂过程的方法。涉及反应中间体捕获、光谱学以及密度泛函理论计算的串联方法揭示了菲咯啉阳离子的双重作用。
