BF<sub>3</sub> ⋅ Et<sub>2</sub>O Promoted Inverse‐Electron‐Demand Oxa‐Diels‐Alder Reaction of Alkylidene Isoxazol‐5‐ones with Unactivated Alkenes
Yu Zheng, Shencheng Qian, Pengcheng Xu, Tianting Ma, Shenlin Huang
Abstract
Abstract The synthesis of fused dihydropyran isoxazole derivatives has been developed by employing an intermolecular inverse‐electron‐demand Diels‐Alder reaction of readily available alkylidene isoxazol‐5‐ones with unactivated alkenes. The reaction was promoted by inexpensive and commercially available BF 3 ⋅ Et 2 O without the use of metal Lewis acids. This cycloaddition transformation could proceed under mild conditions with broad substrate scope, providing a variety of bicyclic 5,6‐dihydro‐4 H ‐pyrano[3,2‐ d ]isoxazoles. magnified image
Topics & Concepts
ChemistryCycloadditionIsoxazoleIntermolecular forceBicyclic moleculeLewis acids and basesSubstrate (aquarium)Medicinal chemistryDihydropyranOrganic chemistryCatalysisMoleculeOceanographyGeologyChemical Synthesis and AnalysisSynthetic Organic Chemistry MethodsSynthesis and Catalytic Reactions