作者:Yuta Fujiwara、Janice A. Dixon、Fionn O’Hara、Erik Daa Funder、Darryl D. Dixon、Rodrigo A. Rodriguez、Ryan D. Baxter、Bart Herlé、Neal Sach、Michael R. Collins、Yoshihiro Ishihara、Phil S. Baran
DOI:10.1038/nature11680
日期:2012.12.6
It is shown that zinc sulphinate salts can be used to transfer alkyl radicals to heterocycles, allowing for the mild, direct and operationally simple formation of medicinally relevant carbonâcarbon bonds while reacting in a complementary fashion to other innate carbonâhydrogen functionalization methods. Nitrogen-rich heterocycles feature widely in pharmaceuticals, and their synthesis has been simplified by a series of advances in transition-metal-mediated cross-coupling reactions. However, the development of practical and selective CâH functionalization methods that do not rely upon pre-functionalized starting materials is an underdeveloped area. Here the authors report that zinc sulphinate salts can be used to transfer alkyl radicals to heterocycles, allowing for a mild, direct and operationally simple formation of medicinally relevant CâC bonds while reacting in an orthogonal fashion to other innate CâH functionalization methods. Nitrogen-rich heterocyclic compounds have had a profound effect on human health because these chemical motifs are found in a large number of drugs used to combat a broad range of diseases and pathophysiological conditions. Advances in transition-metal-mediated cross-coupling have simplified the synthesis of such molecules; however, CâH functionalization of medicinally important heterocycles that does not rely on pre-functionalized starting materials is an underdeveloped area1,2,3,4,5,6,7,8,9. Unfortunately, the innate properties of heterocycles that make them so desirable for biological applicationsâsuch as aqueous solubility and their ability to act as ligandsârender them challenging substrates for direct chemical functionalization. Here we report that zinc sulphinate salts can be used to transfer alkyl radicals to heterocycles, allowing for the mild (moderate temperature, 50â°C or less), direct and operationally simple formation of medicinally relevant CâC bonds while reacting in a complementary fashion to other innate CâH functionalization methods2,3,4,5,6 (Minisci, borono-Minisci, electrophilic aromatic substitution, transition-metal-mediated CâH insertion and CâH deprotonation). We prepared a toolkit of these reagents and studied their reactivity across a wide range of heterocycles (natural products, drugs and building blocks) without recourse to protecting-group chemistry. The reagents can even be used in tandem fashion in a single pot in the presence of water and air.
研究表明,亚磺酸锌盐可用于将烷基自由基转移到杂环上,从而在与其他固有的碳氢官能化方法互补反应的同时,温和、直接且操作简便地形成具有药物相关性的碳-碳键。含氮杂环在药物中广泛存在,过渡金属介导的交叉偶联反应的一系列进展简化了它们的合成。然而,不依赖预官能化起始材料的实用且选择性的碳氢官能化方法是一个发展不足的领域。在这里,作者报道亚磺酸锌盐可用于将烷基自由基转移到杂环上,从而在与其他固有的碳氢官能化方法正交反应的同时,温和、直接且操作简便地形成具有药物相关性的碳-碳键。含氮杂环化合物对人类健康产生了深远影响,因为这些化学基元存在于大量用于对抗广泛疾病和病理生理条件的药物中。过渡金属介导的交叉偶联的进展简化了这些分子的合成;然而,不依赖预官能化起始材料的具有药物重要性的杂环的碳氢官能化是一个发展不足的领域。不幸的是,杂环的天生特性使其在生物应用中如此受欢迎,例如水溶性和作为配体的能力,这使得它们成为直接化学官能化的具有挑战性的底物。在这里,我们报道亚磺酸锌盐可用于将烷基自由基转移到杂环上,从而在与其他固有的碳氢官能化方法互补反应的同时,温和(中温,50°C或更低)、直接且操作简便地形成具有药物相关性的碳-碳键。我们准备了一套这些试剂,并在不借助于保护基化学的情况下,研究了它们在广泛的杂环(天然产物、药物和构建块)中的反应性。这些试剂甚至可以在有水和空气的情况下单锅串联使用。