Cascade Amination/Cyclization/Aromatization Process for the Rapid Construction of [2,3‑c]Dihydrocarbazoles and [2,3‑c]Carbazoles

An intramolecular cascade amination/cyclization/aromatization reaction of functionalized alkylidenecyclopropanes has been developed in the presence of silver acetate, affording a variety of [2,3-c]­dihydrocarbazoles and [2,3-c]­carbazoles in moderate to excellent yields. The mechanistic investigations revealed that this cascade reaction proceeds through a radical initiated process. Moreover, further transformations for the synthesis of eustifoline-D and an OLED exhibit a potential synthetic utility of this method.

本研究开发了在乙酸银(silver acetate)作用下的官能化亚甲基环丙烷(functionalized alkylidenecyclopropanes)分子内级联胺化/环化/芳构化反应，可合成一系列[2,3-c]二氢咔唑([2,3-c]dihydrocarbazoles)与[2,3-c]咔唑([2,3-c]carbazoles)，产物收率处于中等至优异水平。机理研究表明，该级联反应经由自由基引发过程(radical initiated process)进行。此外，将该方法用于欧斯托非林D(eustifoline-D)及有机发光二极管(Organic Light-Emitting Diode, OLED)相关化合物的合成，展现出该方法具备良好的合成应用潜力。