Electrochemical chlorination and bromination of electron-deficient C H bonds in quinones, coumarins, quinoxalines and 1,3-diketones
作者:Dan Yu、Ruixue Ji、Zhihui Sun、Wenjie Li、Zhong-Quan Liu
DOI:10.1016/j.tetlet.2021.153514
日期:2021.12
The electrochemistry-promoted chlorination and bromination of electron-deficient CH bonds was developed, using quinones, coumarins, quinoxalines and 1,3-diketones. This protocol features readily available and safe halogen sources (hydrochloric acid and KBr), high site-selectivity and mild reaction conditions. It could provide an efficient access to a series of chlorinated and brominated quinones, coumarins
Enantioselective and Structure-Selective Diels−Alder Reactions of Unsymmetrical Quinones Catalyzed by a Chiral Oxazaborolidinium Cation. Predictive Selection Rules
作者:Do Hyun Ryu、Gang Zhou、E. J. Corey
DOI:10.1021/ja049323b
日期:2004.4.1
The chiral oxazaborolidinium cation 1 promotes Diels-Alder reactions between 2-triisopropylsilyloxy-1,3-butadiene and a number of unsymmetrical 1,4-benzoquinones in a highly enantioselective and structurally selective manner. The basis for the enantioselectivity is explained rationally in terms of a preferred type of transition-state assembly. Selection rules have been developed that allow the prediction of the principal reaction product of Diels-Alder reaction between unsymmetrical diene and quinone components.