Base‐Promoted Cycloaddition of γ‐Hydroxy‐ and δ‐Hydroxy‐α,β‐Unsaturated Carbonyls with Azaoxyallyl Cations: Rapid Synthesis of <i>N,O</i>‐Heterocycles
Eun Chae Son, Jiseon Lee, Sung‐Gon Kim
Abstract
Metal‐free and environmentally friendly synthesis of morpholin‐3‐one and 1,4‐oxazepan‐3‐one skeletons was achieved by the cycloaddition reaction of alcohol‐tethered enones and α‐halohydroxamates. This transformation was proposed to proceed through the addition of the hydroxyl group in the enone to an in‐situ generated azaoxyallyl cation followed by intramolecular aza‐Michael‐type trapping. Accordingly, morpholin‐3‐ones and 1,4‐oxazepan‐3‐ones could be generated from γ‐hydroxy and δ‐hydroxy enones, respectively, in a highly diastereoselective manner.
Topics & Concepts
ChemistryCycloadditionIntramolecular forceEnoneMichael reactionAlcoholMedicinal chemistryBase (topology)StereochemistryOrganic chemistryCatalysisMathematicsMathematical analysisSynthesis and Biological EvaluationStructural and Chemical Analysis of Organic and Inorganic CompoundsSynthesis and Reactions of Organic Compounds