Although 3-azoindoles have recently emerged as an appealing family of photoswitch molecules, the synthesis of such compounds has been poorly covered in the literature. Herein a high-yielding and operationally simple protocol is reported allowing the synthesis of 3-azoindoles, featuring important steric hindrance around the azo motif. Remarkably, this C–H coupling is characterized by excellent atom economy and occurs under metal-free conditions, at room temperature, and within few minutes, delivering the expected products in excellent yields (quantitatively in most of the cases). Accordingly, a library of new molecules, with potential applications as photochromic compounds, is prepared.

中文翻译：

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通过无金属的吲哚CH键官能团高效合成受阻3-偶氮吲哚

尽管3-偶氮吲哚最近已成为光开关分子的引人注目的家族，但是在文献中很少涉及这类化合物的合成。本文报道了高产率且操作简单的方案，其允许合成3-偶氮吲哚，其在偶氮基序周围具有重要的空间位阻。值得注意的是，这种C–H偶联的特点是出色的原子经济性，发生在无金属条件下，室温下和几分钟之内，从而以优异的产率提供了预期的产物（在大多数情况下是定量的）。因此，制备了具有潜在应用作为光致变色化合物的新分子的文库。