DABCO-Catalyzed [4 + 2] Annulation of 5-Methylenehex-2-ynedioates with Electron-Deficient Alkenes.

Herein, we describe a DABCO-catalyzed [4 + 2] annulation between 5-methylenehex-2-ynedioates and electron-deficient olefins to afford functionalized cyclohexadienes in good yields under mild conditions. The use of β- and ε-carbons of the substrates for C-C bond formation is distinct from previous reports showing a substrate-controlled divergent reactivity. The annulation is believed to proceed in domino cyclization initiated by a cross Rauhut-Currier reaction.