Synthesis of Polycarbonyl Pyrroles via K2S2O8-Mediated Oxidative Cyclization of Enamines.

A novel K2S2O8-promoted oxidative cyclization of enamines is described. A variety of enamines having diverse functional groups and substitution patterns react well using K2S2O8 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.