Direct Access to Pyrrolyltripyrrins and Calixsmaragdyrin from S N Ar 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 S N Ar reaction on α,α'-dibromotripyrrins using various pyrroles or indoles. A representative calixsmaragdyrin was prepared via the 2-fold S N Ar 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.