Palladium‐Catalyzed Asymmetric [4+2] Cycloaddition of 2‐Methylidenetrimethylene Carbonate with Alkenes: Access to Chiral Tetrahydropyran‐Fused Spirocyclic Scaffolds
Biming Mao, Honglei Liu, Zhengyang Yan, Yi Xu, Jiaqing Xu, Wei Wang, Yongjun Wu, Hongchao Guo
Abstract
A palladium-catalyzed asymmetric [4+2] cycloaddition of 2-methylidenetrimethylene carbonate with alkenes derived from pyrazolones, indandione, or barbiturate has been successfully developed, affording pharmacologically interesting chiral tetrahydropyran-fused spirocyclic scaffolds. The target compounds were generated in good to excellent yields and with high enantioselectivity (up to 99 % ee). Furthermore, this cycloaddition reaction could be efficiently scaled up, and several synthetic transformations were accomplished for the construction of other useful chiral spiropyrazolone and spiroindandione derivatives.
Topics & Concepts
TetrahydropyranPalladiumCycloadditionCatalysisChemistryCarbonateOrganic chemistryRing (chemistry)Synthesis and Catalytic ReactionsCatalytic C–H Functionalization MethodsAsymmetric Synthesis and Catalysis