A regioselective Markovnikov hydroarylation of arylcyclobutene has been developed using Brønsted acid catalysis through a protonation/Friedel‐Crafts sequence. The metal‐free catalytic reaction is operationally simple and feasible compared to previous reports that utilized elaborate arylcyclobutene and specific polyfluorinated reagents, affording a variety of gem‐diaryl‐ substituted arylcyclobutene in good to excellent yields. The possible mechanism of the reaction has been explored through step‐by‐step control experiments. This protocol involving indole in gem‐diaryl‐substituted cyclobutene scaffolds not only enriches the applications of Brønsted acid catalyzed hydroarylation, but also paves the way for a more extensive access to potential bioactive cyclobutanes structures.

中文翻译：

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布朗斯台德酸催化芳基环丁烯的马尔可夫尼科夫氢芳基化：生成二芳基取代环丁烷的路线

使用布朗斯台德酸催化，通过质子化/弗里德尔-克拉夫茨序列开发了芳基环丁烯的区域选择性马尔可夫尼科夫加氢芳基化。与之前使用精心设计的芳基环丁烯和特定多氟化试剂的报道相比，无金属催化反应操作简单且可行，以良好至优异的收率提供了各种偕二芳基取代的芳基环丁烯。通过逐步控制实验探索了该反应的可能机制。该方案涉及偕二芳基取代的环丁烯支架中的吲哚，不仅丰富了布朗斯台德酸催化加氢芳基化的应用，而且为更广泛地获得潜在的生物活性环丁烷结构铺平了道路。