Highly Efficient and Expedient Synthesis of 5-Hydroxy-1H-pyrrol-2-(5H)-ones from FeCl₃-Catalyzed Tandem Intramolecular Enaminic Addition of Tertiary Enamides to Ketones and 1,3-Hydroxy Rearrangement

Catalyzed by FeCl₃ under very mild conditions, tertiary enamides underwent a highly efficient intramolecular enaminic addition reaction to the ketonic carbonyls followed by 1,3-hydroxy rearrangement to produce 5-hydroxy-1H-pyrrol-2(5H)-ones in excellent yields.