Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
Org Lett. 2020 Mar 6;22(5):2017-2021. doi: 10.1021/acs.orglett.0c00397. Epub 2020 Feb 20.
Herein we report a redox cyclization of amides and sulfonamides with nitrous oxide (NO) for the direct synthesis of heterocycles. Various amides and sulfonamides could undergo directed ortho metalation (DoM) by treatment with BuLi, and the lithium intermediate could be trapped by NO gas to achieve redox cyclization. NO serves as a N-atom donor to mediate the intramolecular coupling of lithium species toward heterocycle formation with free external oxidant. This protocol offers a direct synthesis of heterocycles with features of readily available starting materials, simple operation, and a broad substrate scope.
在此，我们报告了酰胺和磺酰胺与一氧化二氮（NO）的氧化还原环化反应，用于直接合成杂环。各种酰胺和磺酰胺可以通过与 BuLi 处理进行定向邻位金属化（DoM），并且锂中间体可以被 NO 气体捕获以实现氧化还原环化。NO 用作 N-原子供体，介导锂物种的分子内偶联，以形成具有自由外部氧化剂的杂环。该方案提供了一种具有易得起始原料、操作简单和广泛底物范围的杂环直接合成方法。
