One-pot, Solvent-free Cascade Michael-reductive Cyclization Reaction for the Synthesis of Ethyl 3,5-disubstituted-1H-pyrrole-2-carboxylates Under Microwave Irradiation

An efficient, one-pot, solvent-free synthesis of ethyl 3,5-disubstituted-1H-pyrrole-2-carboxylate is achieved by a reaction of 1,3-disubstituted propen-2-one and ethylnitroacetate, in presence of diethylamine (Et2NH) and triethylphosphite (P(OEt)3) under microwave (MW) irradiation via cascade Michael-reductive cyclization. The mechanistic outcome of the reaction has also been described. This protocol establishes an easy access to disubstituted-1H-pyrrole-2- carboxylates in one pot.