Iron-catalyzed intramolecular acyl nitrene/alkyne metalation for the synthesis of pyrrolo[2,1-a]isoindol-5-ones.

In this work, by using N-methoxybenzamides as efficient acyl nitrene precursors, an iron-catalyzed acyl nitrene/alkyne metalation is reported for the synthesis of pyrrolo[2,1-a]isoindol-5-ones. In the reaction, a 5-exo-dig acyl nitrene/alkyne metalation is specifically observed; a counter anion-aided acyl nitrene/alkyne metalation accounts for the formation of pyrrolo[2,1-a]isoindol-5-ones. Moreover, pyrrolo[2,1-a]isoindol-5-ones possess good fluorescence properties exhibiting a long Stokes shift (>100 nm), and have been employed as small molecular probes for the detection of Hg, hydrazine, and cysteine.