A general method is developed to allow de novo construction of quinolines and C2-functionalized quinolines from ortho-alkenyl anilines in the presence of a difluorocarbene precursor. This method exploits a crucial reactivity of in-situ generation of isocyanides from condensation of primary aniline with difluorocarbene. Subsequent α-addition of isocyanide by neighbouring alkenyl group constructs the quinoline ring. Furthermore, when a combination of difluorocarbene precursor and Se are present, selenoisocyanate intermediates are tentatively generated that upon nucleophilic addition by ortho-alkenyl produce 2-SeH quinolines. In the presence of a second nucleophile such as anilines, competing nucleophilic addition of anilines to the selenoisocyanate is preferred, generating selenourea intermediate. Further nucleophilic addition of the ortho-alkenyl to selenourea followed by elimination of H₂Se produces 2-aminoquinolines. This allows one-step multi-component modular preparation of various C2-functionalized quinolines from readily available starting compounds. This method shows good yields, scope and chemoselectivity. It is operationally convenient and friendly without manipulating unpleasant isocyanides. The difluorocarbene-enabled primary amine to isocyanide conversion may be exploited to develop other interesting reactions.

中文翻译：

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Difluorocarbene Incorporation 合成喹啉和 2-官能化喹啉

开发了一种通用方法，以允许在二氟卡宾前体存在下从邻-烯基苯胺从头构建喹啉和 C2 官能化喹啉。该方法利用伯苯胺与二氟卡宾缩合原位生成异氰化物的关键反应性。随后通过相邻的烯基α-加成异氰化物构建喹啉环。此外，当存在二氟卡宾前体和硒的组合时，通过邻位亲核加成，初步生成硒代异氰酸酯中间体。-烯基产生 2-SeH 喹啉。在第二亲核试剂如苯胺的存在下，苯胺与硒代异氰酸酯的竞争性亲核加成是优选的，生成硒脲中间体。邻位-烯基进一步亲核加成到硒脲，然后消除 H ₂ Se 产生 2-氨基喹啉。这允许从容易获得的起始化合物一步多组分模块化制备各种 C2 官能化喹啉。该方法显示出良好的产率、范围和化学选择性。它操作方便且友好，无需处理令人不快的异氰化物。可利用二氟卡宾使伯胺转化为异氰化物来开发其他有趣的反应。