Highly enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone enabled by cooperative organocatalysts
Jiadong Hu, Yu-Qi Gao, Dongyang Xu, Le Chen, Wen Wen, Yi Hou, Lu Chen, Weiqing Xie
Abstract
Herein, we developed an enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone promoted by cooperative organocatalysts, giving access to hybrid flavonoids in excellent enantioselectivities. This reaction took advantage of cycloisomerization of 2-hydroxychalcone to form a transient flavylium under the irradiation of 24 W CFL, which was trapped by the in situ generated chiral enamine intermediate. The synergistic action of chiral phosphoric acid secured the excellent outcome of this reaction by ion-pairing with the transient flavylium.
Topics & Concepts
Enantioselective synthesisChemistryPhosphoric acidCycloisomerizationOrganocatalysisEnamineCatalysisOrganic chemistryCombinatorial chemistryAsymmetric Synthesis and CatalysisOxidative Organic Chemistry ReactionsAlkaloids: synthesis and pharmacology