Enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines
Hui Liu, Yingkun Yan, Jiayan Zhang, Min Liu, Shaobing Cheng, Zhouyu Wang, Xiaomei Zhang
Abstract
The first enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines was realized using a chiral phosphoric acid as catalyst. Various novel (bridged) isoxazoline fused dihydrobenzofurans bearing two continuous quaternary stereocenters were achieved in moderate to good yields (up to 94%) with moderate to good enantioselectivities (up to 98% ee). The absolute configurations of two products were assigned by X-ray crystal structural analyses and a plausible reaction mechanism was proposed.
Topics & Concepts
Enantioselective synthesisStereocenterAnnulationQuinonePhosphoric acidChemistryCatalysisStereochemistryOrganic chemistryCombinatorial chemistryOxidative Organic Chemistry ReactionsCatalytic C–H Functionalization MethodsAsymmetric Synthesis and Catalysis