Asymmetric Michael addition reactions catalyzed by a novel upper-rim functionalized calix[4]squaramide organocatalyst
作者:Ke Yang、Zhiyan Ma、Hong-Xiao Tong、Xiao-Qiang Sun、Xiao-Yu Hu、Zheng-Yi Li
DOI:10.1016/j.cclet.2020.02.057
日期:2020.12
Abstract A novel upper-rim functionalizedcalix[4]squaramide organocatalyst bearing bis-squaramide and cyclohexanediamine scaffolds was designed and prepared to catalyse a serial of asymmetric Michael addition of 1,3-dicarbonyl compounds to α,β-unsaturated carbonyl compounds in high yields (up to 99 %) and good to excellent enantiomeric excesses (up to 99% ee). The comparative experiments indicated
Enantioselective organocatalytic Michael-hemiketalization catalyzed by a trans-bifunctional indane thiourea catalyst
作者:Yaojun Gao、Qiao Ren、Swee-Meng Ang、Jian Wang
DOI:10.1039/c1ob05404j
日期:——
An efficient, convenient and enantioselective Michael-hemiketalization reaction has been developed for the synthesis of naphthoquinones. In this work, a novel trans-bifunctional indane thiourea catalyst has been reported to promote this process to afford high yields (up to 99%) and high to excellent enantiomeric excesses (90–98% ee).
Enantioselective Michael Addition of 2-Hydroxy-1,4-naphthoquinone to β,γ-Unsaturated α-Keto Esters Catalyzed by Binaphthyl-Modified Squaramide
作者:Ji Hyun Lee、Dae Young Kim
DOI:10.5012/bkcs.2013.34.6.1619
日期:2013.6.20
catalyst loading and long reactiontime for high enantioselectivity. Accordingly, the develop-ment of alternative catalysts for the enantioselective Michaeladdition of 2-hydroxy-1,4-naphthoquinones to β,γ-unsatu-rated α-keto esters is highly desirable.As part of our research program related to the develop-ment of synthetic methods for the enantioselective construc-tion of stereogenic carbon centers,