In this article, we introduces a new method for the synthesis of substituted indole by reductive recyclization of bis(5-alkyl-2-furyl)(2-nitroaryl)methane. Bis(5-alkyl-2-furyl)(2-nitroaryl)methane undergo reduction to provide indole or aniline. In the process of research, we found that the chemoselecitivity of reduction was controlled by subtle differences in the electronic effects of the substrate. Mechanistic studies reveal the origin of this chemoselectivity. Our results suggest the two pathways share common nitroxide ion intermediate. Electron donating groups on aromatic ring promote direct reductive from this intermediate to afford aniline product. Alternatively, electron withdrawing groups on aromatic ring enable furan ring opening from nitroxide ion intermediate to generate the indole product.

在本文中，我们介绍了一种通过双（5-烷基-2-呋喃基）（2-硝基芳基）甲烷还原再环化合成取代吲哚的新方法。双(5-烷基-2-呋喃基)(2-硝基芳基)甲烷进行还原以提供吲哚或苯胺。在研究过程中，我们发现还原的化学选择性受底物电子效应的细微差异控制。机理研究揭示了这种化学选择性的起源。我们的结果表明这两种途径共享共同的硝基氧离子中间体。芳环上的给电子基团促进了该中间体的直接还原，得到苯胺产物。或者，芳环上的吸电子基团使硝基氧离子中间体的呋喃开环生成吲哚产物。