Organophotoredox-Catalyzed CDC Reactions for the Synthesis of Diverse Heterocycles via C─N and C─O Bond Formation under Visible Light Irradiation

An efficient construction of C═N and C─O bonds by the metal-free organophotoredox catalyzed intramolecular cross-dehydrogenative coupling of tertiary amines with amides, amines, and acids as nucleophiles is described. A series of 12,13-dihydro-6H-isoquinolino[2,1-a]quinazolin-6-one, 5,6-dihydrobenzo[4,5]imidazo [2,1-a]isoquinoline, and 4b,13-dihydro-6H,12H-benzo[4,5] [1,3]oxazino[2,3-a]isoquinolin-6-one derivatives were prepared in good to excellent yields. All the transformations proceeded smoothly under an oxygen atmosphere, serving as a clean oxidant. Moreover, the current approach was extended for the synthesis of the biologically active natural product, rutaecarpine.