A Concise and Diversity-Oriented Strategy for the Synthesis of Substituted 2-Pyrrolidinones via an Ugi/Intramolecular Inverse Electron Demand Diels-Alder Sequence

The four component Ugi reaction of an aldehyde, 1,3,4-oxadiazol-2-amine, an 3-enoic acid and an isonitrile affords a concise and diversity-oriented access to synthesis of substituted 2-pyrrolidinones via an Ugi/Intramolecular inverse electron demand Diels-Alder sequence. This two-step process proves that Ugi/IMDA reaction cascades with electron-deficient oxadiazole as dienophile on heating is possible leading to [4 + 2] cycloaddition product. In the case of the pharmaceutically related heterocycle 2-pyrrolidinone, this transformation will further expand application and potential itself.