Nitrogen heterocycles play a crucial role in the synthesis of bioactive molecules, prompting extensive research into efficient synthetic strategies. Among these, imine hydrogenation stands out as a vital transformation, with various methodologies developed, including metal-catalyzed and Brønsted acid-catalyzed approaches. However, visible-light-induced imine hydrogenation, a relatively recent advancement, introduces unique opportunities for greener and milder reaction conditions. Herein, we report a novel approach utilizing tetramethylethene as an inert hydrogen source for the visible light-induced hydrogenation of 3-indoles. The non-metal photocatalyst, thioxanthone-TfOH complex (9-HTXTF), demonstrated efficient catalysis under mild conditions, yielding diverse substituted indoline species.

中文翻译：

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使用四甲基乙烯作为惰性氢源进行可见光诱导的 3H-吲哚氢化

氮杂环在生物活性分子的合成中发挥着至关重要的作用，促进了对有效合成策略的广泛研究。其中，亚胺氢化作为一种​​重要的转化脱颖而出，开发了多种方法，包括金属催化和布朗斯台德酸催化方法。然而，可见光诱导的亚胺氢化是一项相对较新的进展，为更环保和更温和的反应条件带来了独特的机会。在此，我们报告了一种利用四甲基乙烯作为惰性氢源进行可见光诱导的 3-吲哚氢化的新方法。非金属光催化剂噻吨酮-TfOH 络合物 (9-HTXTF) 在温和条件下表现出有效的催化作用，产生多种取代的二氢吲哚物种。