Mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), a novel oxidative coupling of hydrazones and 1,3-diarylpropenes has been disclosed to generate appealing β,γ-unsaturated hydrazones, which further undergo 5-exo-trig or 6-endo-trig cascade cyclization to give the respective 1,2-dihydropyridazines or pyrazoles selectively under metal-free conditions. The mechanisms of the coupling and subsequent cyclization are proposed.

A DDQ-mediated tandem reaction of easily available o-hydroxy­aryl enaminones and cycloheptatriene is disclosed. It provides an effective and convenient method for the synthesis of 3-(cycloheptatrienyl)-substituted chromones in moderate to excellent yields with good functional group tolerance; this reaction involves an oxidative coupling and intramolecular annulation pathway.