Acridine Photocatalysis: Insights into the Mechanism and Development of a Dual-Catalytic Direct Decarboxylative Conjugate Addition
Acridine Photocatalysis: Insights into the Mechanism and Development of a Dual-Catalytic Direct Decarboxylative Conjugate Addition
复制标题
DOI：
10.1021/acscatal.0c03440
复制
发表时间：
2020-10-02
期刊：
影响因子：
12.9
通讯作者：
Larionov, Oleg, V
中科院分区：
文献类型：
--
作者：
Dang, Hang T.;Haug, Graham C.;Larionov, Oleg, V
共轭加成是合成上最有用的碳-碳键形成反应之一；然而，通常需要活性碳亲核试剂来实现加成。自由基共轭加成为用方便的自由基前驱体取代活性亲核试剂提供了一条途径。羧酸可以作为简单和稳定的自由基前体通过脱羧基，但活化到反应酯通常是必要的，以促进具有挑战性的脱羧基。在这里，我们报告了一种广泛的羧酸的直接、双催化脱羧基共轭加成，该加成不需要酸预活化，并且通过可见光驱动的吖啶光催化与高效的铜催化循环相结合来实现。机理和计算研究提供了关于配体和金属物种在双重催化过程中的作用以及取代吖啶类化合物的光催化活性的见解。
Conjugate addition is one of the most synthetically useful carbon-carbon bond-forming reactions; however, reactive carbon nucleophiles are typically required to effect the addition. Radical conjugate addition provides an avenue for replacing reactive nucleophiles with convenient radical precursors. Carboxylic acids can serve as simple and stable radical precursors by way of decarboxylation, but activation to reactive esters is typically necessary to facilitate the challenging decarboxylation. Here, we report a direct, dual-catalytic decarboxylative radical conjugate addition of a wide range of carboxylic acids that does not require acid preactivation and is enabled by the visible light-driven acridine photocatalysis interfaced with an efficient copper catalytic cycle. Mechanistic and computational studies provide insights into the roles of the ligands and metal species in the dual-catalytic process and the photocatalytic activity of substituted acridines.