Intramolecular Transamidation of Secondary Amides via Visible-Light-Induced Tandem Reaction

Transformation of secondary amides to N-acylimines was used as an effective strategy to activate otherwise unreactive amide bonds. In this tandem reaction, the Rose Bengal-catalyzed photo-oxidative coupling of arylglycine esters and enamides generates N-acylimines, which undergo intramolecular transamidation and imine hydrolysis to afford bioactive acyl Mannich base derivatives under metal-free and mild conditions.