Synergistic Cu(II)/Amine-Catalyzed Cyclization of Enynone: Assembly of Tetralone and Tetrahydronaphthylimine.

An unprecedented synergistic copper- and amine-catalyzed cyclization of enynone is reported. This reaction features an efficient and straightforward construction of multisubstituted tetralone through an amine-assisted regioselective oxygen atom transfer process and stereoselective intramolecular Michael addition cyclization. Under dehydrative reaction conditions, the synthesis of tetrahydronaphthylimine derivatives with ketone group tolerance is achieved, which could be challenging via traditional methods. The utility of this reaction is demonstrated by further transformations of obtained molecules toward a variety of valuable multisubstituted naphthyl skeletons.