Divergent Aerobic Oxidative Ring-Opening Cascades of Isatins with 1,2,3,4-Tetrahydroisoquinoline

The unprecedented aerobic oxidative ring‐opening‐initiated cascades of isatins with 1,2,3,4‐tetrahydroisoquinoline were explored, in which the reaction sequence could be readily modulated by simply introducing a protecting group in the isatin. Consequently, quinazoline‐2,4‐diones and polycyclic 2,3‐dihydro‐4(1H)‐quinazolinones with potential bioactivities were efficiently assembled in moderate chemical yields. Unprecedented aerobic oxidative ring‐opening‐initiated cascade reactions are observed, and quinazoline‐2,4‐diones and polycyclic 2,3‐dihydro‐4(1H)‐quinazolinones are efficiently assembled in moderate chemical yields.