美国威斯康星大学麦迪逊分校Yoon, Tehshik P.团队报道了Cu（ii）羧酸盐的配体金属电荷转移光激发脱羧交叉亲核偶联。相关研究成果于2022年1月5日发表于国际顶尖学术期刊《Nature Chemistry》。

能够形成碳-氮、碳-氧和碳-碳键的反应是合成化学的核心。然而，通常需要底物预功能化才能在不强制反应条件下实现这种转化。因此，开发大量原料化学品的直接偶联方法对于快速构建复杂分子支架是非常必要的。

该文中，研究人员报道了在可见光照射下，铜介导的羧酸与各种亲核试剂的净氧化脱羧偶联。初步的机理研究表明，该反应中的相关生色团是原位组装的Cu（II）羧酸物种。研究人员认为，可见光激发到配体-金属电荷转移（LMCT）状态会导致自由基脱羧过程，从而引发氧化交叉偶联。该反应适用于多种偶联剂，包括复杂的药物分子，表明这种交叉亲核偶联策略有助于快速合成化合物库以发现新的药物制剂。

附：英文原文

Title: Decarboxylative cross-nucleophile coupling via ligand-to-metal charge transfer photoexcitation of Cu(ii) carboxylates

Author: Li, Qi Yukki, Gockel, Samuel N., Lutovsky, Grace A., DeGlopper, Kimberly S., Baldwin, Neil J., Bundesmann, Mark W., Tucker, Joseph W., Bagley, Scott W., Yoon, Tehshik P.

Issue&Volume: 2022-01-05

Abstract: Reactions that enable carbon–nitrogen, carbon–oxygen and carbon–carbon bond formation lie at the heart of synthetic chemistry. However, substrate prefunctionalization is often needed to effect such transformations without forcing reaction conditions. The development of direct coupling methods for abundant feedstock chemicals is therefore highly desirable for the rapid construction of complex molecular scaffolds. Here we report a copper-mediated, net-oxidative decarboxylative coupling of carboxylic acids with diverse nucleophiles under visible-light irradiation. Preliminary mechanistic studies suggest that the relevant chromophore in this reaction is a Cu(II) carboxylate species assembled in situ. We propose that visible-light excitation to a ligand-to-metal charge transfer (LMCT) state results in a radical decarboxylation process that initiates the oxidative cross-coupling. The reaction is applicable to a wide variety of coupling partners, including complex drug molecules, suggesting that this strategy for cross-nucleophile coupling would facilitate rapid compound library synthesis for the discovery of new pharmaceutical agents.

DOI: 10.1038/s41557-021-00834-8

Source: https://www.nature.com/articles/s41557-021-00834-8