Asymmetric Formal [5 + 2] Annulation of 3-Hydroxyquinolinones and Vinylethylene Carbonates through Pd/Cu Tandem Catalysis

The asymmetric [5 + 2] cycloaddition of VECs remains to be comparatively rare. Herein, we reported an enantioselective formal [5 + 2] annulation of 3-hydroxyquinolinones and vinylethylene carbonates (VECs) through Pd- and Cu-catalyzed tandem allylation/asymmetric [1,3]-rearrangement/hemiketalization sequences. The strategy exhibits good substrate tolerance, affording a wide range of tricyclic quinolinones bearing two adjacent quaternary stereocenters in moderate to good yields with excellent enantioselectivities.