Probing the Mechanism of Bronsted Acid Catalyzed Azlactone Ring Opening by ESI-MS

摘要

Mechanism investigation via ESI(+)-MS/MS revealed azlactone activation by the catalyst CSA to form an ion pairing intermediate, following by nucleophilic attack. No H/D exchange occurs when D2O is used, suggesting that CSA is responsible for the protonation and de-protonation steps.