Synthesis of Tetrasubstituted Unsymmetrical 1,4-Enediones via Copper-Promoted Autotandem Catalysis and Air As the Oxidant

An efficient procedure has been developed for the preparation of tetrasubstituted unsymmetrical 1,4-enediones via copper-promoted autotandem catalysis and air as the oxidant. Various N-nucleophiles are compatible with this reaction, such as morpholine, piperidine, pyrrolidine, arylamines, pyrazole, imidazole, benzimidazole, and benzotriazole. This reaction also has significant advantages in easily available substrates, atom economy, bond-forming efficiency, and environmental benignity.