Synthesis of phenanthrylboroles and formal nitrene insertion to access azaborapyrenes.

Extended conjugation has been introduced into boroles but only on the 2,3- or 4,5-positions of the central BC 4 core. In this work we synthesize phenanthrylboroles that also have conjugation on the 3,4-positions and demonstrate their insertion reactivity with azides to furnish B,N-analogues of pyrene.