γ′‐Selective Functionalization of Cyclic Enones: Construction of a Chiral Quaternary Carbon Center by [4+2] Cycloaddition/Retro‐Mannich Reaction with 3‐Substituted Maleimides

Abstract

AbstractThe first example of organocatalyzed γ′‐selective functionalization of cyclic enones with 3‐substituted maleimides results in the stereoselective construction quaternary carbon center is presented. The reactions provided γ′‐functionalized cyclic enones and β‐functionalized cyclopentenones in good to excellent yields with excellent diastereo‐ and enantioselectivities. DFT calculations indicated that the reaction might proceed as a [4+2] cycloaddition/retro‐Mannich reaction which could explain the unexpected product with a chiral quaternary carbon center and the excellent stereoselectivity.