Chiral Hydroxytetraphenylene-Boron Complex Catalyzed Asymmetric Diels-Alder Cycloaddition of 2'-Hydroxychalcones
Guo-Li Chai1, Yan Qiao2, Ping Zhang1
1Henan Key Laboratory of Organic Functional Molecules and Drug Innovation, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Abstract:
(S)-2,15-Cl2-DHTP-boron complex catalyst for the asymmetric Diels-Alder cycloaddition of 2'-hydroxychalcones and dienes was developed and tested. The resulting cyclohexenes with three chiral centers were obtained in high yields (up to 98%) with excellent stereoselectivities (up to >20:1 endo/exo, >99% ee). This catalytic system features high efficiency, broad substrate scopes, and mild reaction conditions. In addition, a DFT study was performed to explain the stereochemical course of the asymmetric induction.
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