Palladium-catalyzed asymmetric [4+2] annulation of vinyl benzoxazinanones with pyrazolone 4,5-diones to access spirobenzoxazine frameworks
Ben‐Hong Chen, Shuai‐Jiang Liu, Qian Zhao, Qiumeng Hou, Jiali Yuan, Gu Zhan, Qian‐Qian Yang, Wei Huang
Abstract
Herein, a palladium-catalyzed general synthetic strategy to access an attractive and decorated set of chiral spiro derivatives of benzoxazine compounds is unveiled utilizing vinyl benzoxazinanones reacted with pyrazolone 4,5-diones, which extends the application of vinyl benzoxazinanones with ketones. This asymmetric catalytic [4+2] cycloaddition reaction demonstrates a broad substrate scope with functional group tolerance in yields of up to 76% and up to 96% ee. A facile scale-up and straightforward conversion to diversely substituted products verify the synthetic utility of this method.
Topics & Concepts
PyrazoloneAnnulationCatalysisPalladiumCycloadditionSubstrate (aquarium)ChemistryCombinatorial chemistryFunctional groupReaction conditionsMaterial chemistryOrganic chemistryGreen chemistryReaction mechanismPolymerOceanographyGeologyCatalytic C–H Functionalization MethodsCyclopropane Reaction MechanismsSynthesis and Catalytic Reactions