Ligand and Cu free N-arylation of indoles, pyrroles and benzylamines with aryl halides catalyzed by a Pd nanocatalyst

Abstract

Herein, the N-arylation of aromatic heterocycles like indoles and pyrroles is reported by a Pd nanocatalyst under ligand- and Cu-free conditions. The reaction conditions tolerate several functional groups and work very efficiently for aryl iodides and bromides. Aryl chlorides are also successful as the coupling partners albeit with lower yields. The methodology is also applicable for the N-arylation of aliphatic primary amines as demonstrated by the reactions of benzylamine with several aryl iodides as well as bromides. The recyclable Pd nanocatalyst catalyzes the reaction by a heterogeneous mechanism, which has been demonstrated by several techniques including the three phase test and the in situ ICP-MS analysis of the reaction mixture.