Ligand-Controlled Palladium-Catalyzed Asymmetric [4+3] and [2+3] Annulation Reactions of Spirovinylcyclopropyl Oxindoles with <i>o</i>-Quinone Methides
Xiyuan Zhang, Cong Zhang, Bo Jiang, Yanfeng Gao, Xiufang Xu, Zhiwei Miao
Abstract
We herein report regiodivergent ligand-controlled palladium-catalyzed asymmetric cycloaddition reactions between spirovinylcyclopropyl oxindoles and o-quinone methides. Specifically, by using the chiral P,P-ligand Segphos (L5), we obtained various spirooxindole-3,4-benzo[b]oxepanes in moderate to good yields with excellent enantioselectivities via [4+3] cycloaddition reactions. In contrast, reactions involving Trost’s ligand (L7) showed different regio- and stereoselectivities, affording bispirooxindole heterocyclic compounds in good yields via [2+3] cycloaddition reactions.
Topics & Concepts
ChemistryCycloadditionPalladiumAnnulationLigand (biochemistry)CatalysisCombinatorial chemistryQuinoneStereochemistryMedicinal chemistryOrganic chemistryReceptorBiochemistrySynthesis of Indole DerivativesCarbohydrate Chemistry and SynthesisOxidative Organic Chemistry Reactions