Difficult-to-access 4-bromo quinolines are constructed directly from easily prepared ortho-propynol phenyl azides using TMSBr as acid-promoter. The cascade transformation performs smoothly to generate desired products in moderate to excellent yields with good functional groups compatibility. Notably, TMSBr not only acted as an acid-promoter to initiate the reaction, and also as a nucleophile. In addition, 4-bromo quinolines as key intermediates could further undergo the coupling reactions or nucleophilic reactions to provide a variety of functionalized compounds with molecular diversity at C4 position of quinolines.

中文翻译：

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TMSBr 促进邻丙炔苯叠氮化合物级联环化合成 4-溴喹啉及其应用

使用 TMSBr 作为酸促进剂，从容易制备的邻丙炔苯基叠氮化物直接构建难以获得的 4-溴喹啉。级联转化顺利进行，以中等至优异的产率生成所需的产物，并具有良好的官能团兼容性。值得注意的是，TMSBr 不仅充当酸促进剂以引发反应，而且还充当亲核试剂。此外，作为关键中间体的4-溴喹啉可以进一步进行偶联反应或亲核反应，以提供多种在喹啉C4位具有分子多样性的官能化化合物。