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.

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Towards an efficient, mild and sustainable approach for nitroarene hydrogenation by Pd nanoparticles in aqueous medium.

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An efficient one-pot, two-step Pd-catalyzed arsination with n-Bu3SnAsPh2 (1) and sterically hindered aryl iodides (ArI) with different functional groups is reported. The cross-coupling reactions of this stannane with ArI afforded the functionalized triarylarsines in very good isolated yields (71−88%). By using this methodology, a biphenyl arsine ligand, AsPh2(bph), was achieved, and its use as ligand in the Pd-catalyzed arsination with RfI to obtain perfluoroalkylarsines is also reported. In this reaction, the activity of a variety of phosphine and arsine ligands was investigated. The new biphenyl arsine ligand AsPh2(bph) proved to be the best one for the arsination reaction with RfI.