Palladium-Catalyzed Asymmetric (2+3) Annulation of p-Quinone Methides with Trimethylenemethanes: Enantioselective Synthesis of Functionalized Chiral Spirocyclopentyl p-Dienones

A novel asymmetric catalytic (2+3) annulation of p-quinone methides with CN-substituted trimethylene-methane is described under palladium catalysis, providing an alternative approach for the enantioselective construction of highly functionalized chiral spirocyclopentyl p-dienones. Driven by the significant improvement in the reactivity and enantioselectivity, a novel type of non-C-2-symmetric phosphoramidite ligand from the chirality-matched combination of (S)-BINOL and sterically demanding amine derived from L-hydroxyproline is evolved and explored for the protocol presented here.