Transition metal-catalyzed direct C−H bond functionalization is recognized as an efficient strategy to assemble heterocyclic frameworks. For this purpose, directing groups (DGs) installation on an organic molecule has remained a widely exploited strategy for the years. The installation of directing groups, especially for the amine, alcohol and thiol containing reactants and their removal after the reaction need additional steps. In this regard, the use of free amine, hydroxyl and sulfhydryl as directing groups in native form is advantageous and in recent times, these transformations have stirred undisputable advancements for applications to heterocycle synthesis. In this review, the aromatic sp²-C attached free amine, hydroxyl and sulfhydryl as native functionalities are shown to be useful for the construction of five to seven-membered N-, O- and S-heterocycles.

中文翻译：

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游离胺、羟基和巯基定向的 C−H 官能化和环化：在杂环合成中的应用

过渡金属催化的直接 C-H 键官能化被认为是组装杂环框架的有效策略。为此，多年来，在有机分子上安装定向基团 (DG) 一直是一种广泛使用的策略。定向基团的安装，特别是对于含有胺、醇和硫醇的反应物以及它们在反应后的去除需要额外的步骤。在这方面，使用游离胺、羟基和巯基作为天然形式的导向基团是有利的，并且最近，这些转变在杂环合成中的应用已经引起了无可争议的进步。在这篇综述中，芳香族 sp ²-C 连接的游离胺、羟基和巯基作为天然官能团被证明可用于构建五至七元N-、O-和S-杂环。