Asymmetric Synthesis of Spiropyrazolones via Chiral Pd(0)/Ligand Complex-Catalyzed Formal [4+2] Cycloaddition of Vinyl Benzoxazinanones with Alkylidene Pyrazolones
Jia‐Ming Guo, Xiao‐Zu Fan, Huihui Wu, Zhe Tang, Xiao‐Fan Bi, Heng Zhang, Lu‐Yu Cai, Hong‐Wu Zhao, Qi‐Di Zhong
Abstract
In the presence of the chiral Pd(0)/ligand complex, vinyl benzoxazinanones underwent the [4+2] cycloaddition with alkylidene pyrazolones smoothly and delivered spiropyrazolones in reasonable yields, diastereoselectivities, and eneantioselectivities (up to >99% yield, >99:1 dr and 99% ee). The absolute configuration of the obtained spiropyrazolones was unambiguously characterized with the use of X-ray single-crystal structure analysis. Moreover, the reaction mechanism was assumed to interpret the formation of the target compounds.
Topics & Concepts
ChemistryPyrazolonesCycloadditionLigand (biochemistry)CatalysisEnantioselective synthesisCombinatorial chemistryFormal synthesisChiral ligandOrganic chemistryReceptorBiochemistrySynthesis and Catalytic ReactionsCyclopropane Reaction MechanismsAsymmetric Synthesis and Catalysis