One-Pot Three-Component Synthesis of Pyrrolidin-2-ones via a Sequential Wittig/Nucleophilic Addition/Cyclization Reaction

A new efficient synthesis of pyrrolidin-2-ones via sequential Wittig reaction/nucleophilic addition/cyclization was developed. The Wittig reaction of the phosphoranes with isocyanates produced ketenimine intermediates that were then treated with primary amines to give amidines, which were treated with catalytic sodium alkoxide to give 2-imino-5-oxopyrrolidine-3-carboxylates in good yields.