Synthesis of Polycarbonyl Pyrroles via K<sub>2</sub>S<sub>2</sub>O<sub>8</sub>‑Mediated Oxidative Cyclization of Enamines

A novel K<sub>2</sub>S<sub>2</sub>O<sub>8</sub>-promoted oxidative cyclization of enamines is described. A variety of enamines having diverse functional groups and substitution patterns react well using K<sub>2</sub>S<sub>2</sub>O<sub>8</sub> as the oxidant in the absence of catalyst. This protocol provides a very simple route for the synthesis of polycarbonyl pyrroles and has the advantages of readily available starting materials, mild reaction conditions, and a wide scope of substrates.