A method for the intramolecular addition of triarylmethanes to alkynes has been developed. The reaction was efficiently promoted by KOtBu/DMF without any transition-metal catalyst. A variety of indene derivatives were prepared in moderate to good yields. A cascade cyclization of 2-alkyl-substituted substrates at elevated reaction temperature gave bicyclic indene derivatives. The reaction is proposed to proceed through the generation of a triphenylmethyl radical.

中文翻译：

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由 KOtBu/DMF 促进三芳基甲烷与炔烃的分子内加成：茚衍生物的合成方法

已经开发了一种将三芳基甲烷分子内加成到炔烃的方法。在没有任何过渡金属催化剂的情况下，KOtBu/DMF 有效地促进了反应。以中等至良好的产率制备了多种茚衍生物。在升高的反应温度下，2-烷基取代底物的级联环化得到双环茚衍生物。建议该反应通过生成三苯甲基自由基进行。