Catalytic Asymmetric Tandem Cycloisomerization/[5+2] Cycloaddition Reaction of <i>N</i>-Aryl Nitrone Alkynes with Methyleneindolinones
Bowen Hu, Xiying Zhang, Yuhao Mo, Jinzhao Li, Lili Lin, Xiaohua Liu, Xiaoming Feng
Abstract
An asymmetric tandem cycloisomerization and intermolecular [5+2] cycloaddition reaction of 2-ethynylphenyl-substituted nitrones with methyleneindolinones was realized. The process includes the palladium(II)-promoted in situ formation of azomethine ylide and the following chiral N,N′-dioxide-Co(II) complex-catalyzed regio-, diastereo-, and enantioselective [5+2] cycloaddition reaction. The desired spiro-tropanyl oxindoles were obtained in good yields with excellent dr and ee values. On the basis of the determination of the catalyst structure, a possible transition state model was proposed.
Topics & Concepts
CycloisomerizationNitroneChemistryCycloadditionCatalysisTandemArylCombinatorial chemistryMedicinal chemistryOrganic chemistryComposite materialAlkylMaterials scienceCatalytic Alkyne ReactionsCyclopropane Reaction MechanismsOxidative Organic Chemistry Reactions