Carbene insertion into the C(sp²)−H bonds of internal alkenes was enabled in air by HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) as both the mediator and solvent through its cooperation with borane B(C₆F₅)₃ as the catalyst. 3-Diazooxindoles and 3-diazoindolin-2-imines were amenable to work as the carbene precursors, and α-oxo ketene dithioacetals acted as the internal alkenes at ambient temperature. The present synthetic protocol features metal-free conditions, diverse substituent tolerance, and 47–84% yields, offering an efficient route to 3-vinylated oxindole and indole derivatives.

中文翻译：

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在无金属条件下硼烷催化、HFIP 辅助卡宾插入内部烯基 C−H 键

通过HFIP （ 1,1,1,3,3,3-六氟^-2-丙醇）作为介体和溶剂，通过与硼烷B(C ₆ F ₅ ) ₃为催化剂。3-Diazooxindoles 和 3-diazoindolin-2-imines 适合作为卡宾前体，α - oxo 乙烯酮二硫缩醛在环境温度下充当内部烯烃。目前的合成方案具有无金属条件、不同的取代基耐受性和 47-84% 的产率，为 3-乙烯基化羟吲哚和吲哚衍生物提供了有效途径。