Budén María E, Vaillard Victoria A, Martin Sandra E, Rossi Roberto A
INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Argentina.
J Org Chem. 2009 Jun 19;74(12):4490-8. doi: 10.1021/jo9006249.
The synthesis of a series of substituted 9H-carbazoles by the photostimulated S(RN)1 substitution reaction with diarylamines as starting substrate was performed. The diarylamines were obtained by two approaches, the Pd-catalyzed reactions (Buchwald-Hartwig) or Cu-catalyzed reactions of 2-haloanilines with aryl halides, or 2-bromoiodobenzene with anilines, with moderate to very good isolated yields (45-89%). Through an intramolecular C-C bond formation of diarylamines by the S(RN)1 mechanism, carbazoles were achieved. These reactions proceeded synthetically in very good to excellent yields (81-99%) in liquid ammonia and DMSO. The reaction of N-(2-bromophenyl)-2-phenylbenzenamine gave 1-phenyl-9H-carbazole (38%) and the isomer 9H-tribenz[b,d,f]azepine (58%). By using this methodology, 9H-carbazoles, substituted 9H-carbazoles, benzocarbazoles, and even 3,3'-bi(9H-carbazole) were obtained by a double S(RN)1 reaction with benzidine.
以二芳基胺为起始底物，通过光刺激的S(RN)1取代反应进行了一系列取代9H-咔唑的合成。二芳基胺可通过两种方法获得，即钯催化反应（布赫瓦尔德-哈特维希反应）或铜催化的2-卤代苯胺与芳基卤化物的反应，或2-溴碘苯与苯胺的反应，分离产率中等至非常好（45-89%）。通过S(RN)1机理使二芳基胺进行分子内C-C键形成，从而得到咔唑。这些反应在液氨和二甲基亚砜中以非常好至优异的产率（81-99%）进行合成。N-(2-溴苯基)-2-苯基苯胺的反应得到1-苯基-9H-咔唑（38%）和异构体9H-三苯并[b,d,f]氮杂䓬（58%）。通过使用这种方法，通过与联苯胺的双S(RN)1反应获得了9H-咔唑、取代的9H-咔唑、苯并咔唑，甚至3,3'-联(9H-咔唑)。
