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 trimethylenemethane 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.