Synthesis of carbazoles by intramolecular arylation of diarylamide anions.
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.
Budén
María E
ME
INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Argentina.
Vaillard
Victoria A
VA
Martin
Sandra E
SE
Rossi
Roberto A
RA
D000577:Amides / Q000737:chemistry*; D000814:Aniline Compounds / Q000737:chemistry*; D001555:Benzene Derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D001560:Benzidines / Q000737:chemistry; D002227:Carbazoles / Q000138:chemical synthesis*; D007700:Kinetics; D055668:Photochemical Processes
D000577:Amides; D000814:Aniline Compounds; D001555:Benzene Derivatives; D001560:Benzidines; D002227:Carbazoles; C029876:benzidine