Rauhut-Currier-Initiated Organocascade Reaction: Synthesis of Substituted Dispirocyclohexanes through a [2+2+2] Strategy between 2-Arylideneindan-1,3-diones and Activated Alkenes

For the synthesis of multisubstituted dispirocyclohexane derivatives, a Rauhut-Currier-initiated organocascade reaction between 2-arylideneindan-1,3-diones and activated alkenes in the presence of diazabicyclo[2.2.2]octane (DABCO) was demonstrated. The functionalized dispirocyclohexanes with a wide range of substituents were obtained in satisfactory to excellent chemical yields (58-99%) with high chemo- and diastereoselectivities (>95:5 dr). This organocatalytic reaction proceeded smoothly through Michael/Michael cyclization, which involves the formation of three new carbon-carbon bonds with simultaneous construction of two all-carbon spiro quaternary centers.