Brønsted acid catalyzed azlactone ring opening by nucleophiles

Brønsted acid catalyzed azlactone ring opening in the presence of different nucleophiles leading to the efficient synthesis of protected amides and amino esters is presented. Sixteen compounds were synthesized in good to excellent isolated yields. Mechanism investigation by using ESI(+)-MS/MS revealed that the CSA catalyst promotes azlactone activation for electrophilic attack facilitating therefore the attack of the nucleophile that leads to ring opening and protonation.

Graphical abstractDownload full-size imageBrønsted acid catalyzed azlactone ring opening in the presence of different nucleophiles leading to the efficient synthesis of protected amides and amino esters is presented. Sixteen compounds were synthesized in good to excellent isolated yields. Mechanism investigation by using ESI(+)-MS/MS revealed that the CSA catalyst promotes azlactone activation for electrophilic attack facilitating therefore the attack of the nucleophile that leads to ring opening and protonation.