Light and acid steer a radical addition So-called Minisci reactions have been used for decades in pharmaceutical and agrochemical synthesis to make carbon-carbon bonds. The reactions link carbon radicals to the carbon centers adjacent to nitrogen in pyridine rings. Proctor et al. devised a method to steer these reactions to just one of two possible mirror-image products. To make the radicals, they prepared derivatives of widely available amino acids and then activated them with an iridium photocatalyst. At the same time, a chiral phosphoric acid catalyst was used to activate the pyridine and bias the reaction geometry. Science, this issue p. 419 Pairing a photocatalyst with a chiral acid renders a widely used carbon-carbon bond-forming reaction asymmetric. Basic heteroarenes are a ubiquitous feature of pharmaceuticals and bioactive molecules, and Minisci-type additions of radical nucleophiles are a leading method for their elaboration. Despite many Minisci-type protocols that result in the formation of stereocenters, exerting control over the absolute stereochemistry at these centers remains an unmet challenge. We report a process for addition of prochiral radicals, generated from amino acid derivatives, to pyridines and quinolines. Our method offers excellent control of both enantioselectivity and regioselectivity. An enantiopure chiral Brønsted acid catalyst serves both to activate the substrate and induce asymmetry, while an iridium photocatalyst mediates the required electron transfer processes. We anticipate that this method will expedite access to enantioenriched small-molecule building blocks bearing versatile basic heterocycles.

中文翻译：

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催化对映选择性 Minisci 型加成杂芳烃

光和酸引导自由基加成 几十年来，所谓的 Minisci 反应已在制药和农用化学品合成中用于制造碳-碳键。该反应将碳自由基连接到吡啶环中与氮相邻的碳中心。普罗克特等人。设计了一种方法来将这些反应引导到两种可能的镜像产物中的一种。为了制造自由基，他们制备了广泛使用的氨基酸衍生物，然后用铱光催化剂激活它们。同时，手性磷酸催化剂用于活化吡啶并偏置反应几何结构。科学，这个问题 p。419 将光催化剂与手性酸配对可使广泛使用的碳-碳键形成反应不对称。碱性杂芳烃是药物和生物活性分子的普遍特征，自由基亲核试剂的 Minisci 型加成是其制备的主要方法。尽管许多 Minisci 类型的协议会导致立体中心的形成，但对这些中心的绝对立体化学施加控制仍然是一个未解决的挑战。我们报告了将氨基酸衍生物产生的前手性自由基添加到吡啶和喹啉的过程。我们的方法提供了对映选择性和区域选择性的出色控制。对映纯手性布朗斯台德酸催化剂既可以激活底物，又可以诱导不对称性，而铱光催化剂则介导所需的电子转移过程。我们预计这种方法将加快获得对映体富集的小分子结构单元，这些结构单元具有多功能的基本杂环。