Synthesis of carbazoles by intramolecular arylation of diarylamide anions

MARÍA E. BUDÉN; VICTORIA A. VAILLARD; SANDRA E. MARTÍN; ROBERTO A. ROSSI

JOURNAL OF ORGANIC CHEMISTRY

ACS publication, American Chemical Society

Lugar: Washington, DC; Año: 2009 vol. 74 p. 4490 - 4498

0022-3263

The synthesis of a series of substituted 9H-carbazoles by the phostimulated SRN1 substitution reactions 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-bromiodobenzene with anilines, with moderate to very good isolated yields (45-89%). Through an intramolecular C-C bond formationof diarylamines by the SRN1 mechasnism, carbazoles were achieved. These reactions proceeded synthetically in very good to excellent yields (81-99%) in liquid amonia and DMSO. The reaction of N-(2-bromophenyl)-2-phenylbenzeamine gave 1-phenyl, 9H-carbazole (38%) and the isomer 9H-tribenzo[b,d,f] azepine (58%). By using this methdology, 9H-carbazoles, substituted 9H-carbazoles, benzocarbazoles and even 3,3`-bi-(9H-carbazole) were obtained by a double SRN1 reaction with benzidine.