Straightforward Synthesis of Oligopyrroles through a Regioselective SNAr Reaction of Pyrroles and Halogenated Boron Dipyrrins

A novel stepwise and regioselective nucleophilic aromatic substitution (SNAr) reaction of halogenated boron dipyrrins (BODIPYs) with pyrroles has been developed under mild conditions with no catalyst needed and shown to be diversity oriented. The resultant pyrrole-substituted BODIPYs are interesting red and near-infrared (NIR) fluorescent dyes with absorption maxima up to 733 nm. Removal of the BF2 protecting group of the 3-pyrrole or 3,5-dipyrrole-substituted BODIPYs provides a facial entry to oligopyrroles with direct 2,2'-bipyrrole linkages.