Organocatalytic Remote Asymmetric Inverse‐Electron‐Demand Oxa‐Diels‐Alder Reaction of Allyl Ketones with Isatin‐Derived Unsaturated Keto Esters
Ye Lin, Xi‐Qiang Hou, Bing‐Yu Li, Da‐Ming Du
Abstract
Abstract A remote cascade asymmetric inverse‐electron‐demand oxa‐Diels‐Alder reaction of allyl ketones with isatin‐derived β , γ ‐unsaturated α ‐keto esters has been developed in the presence of a chiral bifunctional squaramide catalyst. Taking advantage of the secondary amide activating group, a series of enantioenriched 3,4’‐pyranyl spirooxindole derivatives bearing three contiguous chiral centers were attained in high yields (84 to >99%) with excellent enantioselectivities (96–99% ee ). Moreover, the gram‐scale synthesis and the construction of 1‐benzazepine scaffold by the product were also demonstrated. magnified image
Topics & Concepts
ChemistryIsatinSquaramideDiels–Alder reactionBifunctionalAmideCatalysisCascade reactionOrganocatalysisEnantioselective synthesisOrganic chemistryAsymmetric Synthesis and CatalysisSynthetic Organic Chemistry MethodsSynthesis and Catalytic Reactions