Product-selectivity control by the nature of the catalyst: Lewis acid-catalyzed selective formation of ring-fused tetrahydroquinolines and tetrahydroazepines via intramolecular redox reaction

Selective synthesis of ring-fused tetrahydroquinolines and tetrahydroazepines from the same starting materials was achieved by subtle use of the oxophilic Sc(OTf)(3) or carbophilic IPrAuOTf as the catalyst.