Tandem Synthesis of 3,4-Disubstituted Pyrroles from Aldehydes, 1,3-Diketones and TosMIC Under Metal-Free Conditions

The method described herein is an efficient and simple process to obtain 3,4-disubstituted pyrroles. This protocol utilizes the three component reaction of aldehydes, 1,3-dicarbonyls and TosMIC in one pot under metal free conditions with moderate to excellent yields. The mechanism of the reaction involves a Knoevenagel condensation between an aldehyde and dicarbonyl substrate to give unsaturated alkene intermediate which further undergoes Michael addition with TosMIC to provide desired 3,4-disubstituted pyrroles. The scope of the substrate was then explored to understand the diversity of functional group tolerance. A series of 31 examples were generated using the present protocol.