Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
Science. 2017 Mar 31;355(6332):1403-1407. doi: 10.1126/science.aam7975.
Over the past 80 years, phenyl cation intermediates have been implicated in a variety of C-H arylation reactions. Although these examples have inspired several theoretical and mechanistic studies, aryl cation equivalents have received limited attention in organic methodology. Their high-energy, promiscuous reactivity profiles have hampered applications in selective intermolecular processes. We report a reaction design that overcomes these challenges. Specifically, we found that β-silicon-stabilized aryl cation equivalents, generated via silylium-mediated fluoride activation, undergo insertion into sp and sp C-H bonds. This reaction manifold provides a framework for the catalytic arylation of hydrocarbons, including simple alkanes such as methane. This process uses low loadings of Earth-abundant initiators (1 to 5 mole percent) and occurs under mild conditions (30° to 100°C).
在过去的 80 年中，苯阳离子中间体被牵涉到各种 C-H 芳基化反应中。尽管这些例子激发了一些理论和机制研究，但芳基阳离子等价物在有机方法学中受到的关注有限。它们的高能、杂乱无章的反应性阻碍了它们在选择性的分子间过程中的应用。我们报告了一种克服这些挑战的反应设计。具体来说，我们发现通过硅鎓介导的氟化物活化生成的β-硅稳定的芳基阳离子等价物会插入 sp 和 sp^C-H 键中。这种反应机理为烃类的催化芳基化提供了一个框架，包括甲烷等简单的烷烃。这个过程使用低负载量的丰富地球元素引发剂（1 到 5 摩尔%），并在温和的条件下（30°到 100°C）发生。
