Direct Access to Pyrrolyltripyrrins and Calixsmaragdyrin from SNAr Reactions on α,α′-Dibromotripyrrins with Pyrroles or Indoles

Linear π-conjugated oligopyrroles are attractive precursors for the synthesis of expanded porphyrinoids, chemosensors, and supramolecular motifs. We demonstrate a new method for the synthesis of a set of linear pyrrolyltripyrrins and dipyrrolyltripyrrins through a regioselective SNAr reaction on α,α′-dibromotripyrrins using various pyrroles or indoles. A representative calixsmaragdyrin was prepared via the 2-fold SNAr reaction between α,α′-dibromotripyrrin and dipyrromethene through a convergent [3 + 2] strategy. These oligopyrroles showed intense deep red absorptions with an interesting pH response.