Reinvestigation of synthesis of halo-substituted 3-phenyl-1-(2-pyridyl)-2-propen-1-ones (azachalcones). A tandem reaction for formation of penta-substituted cyclohexanols
作者:Chia-Wai Li、Tzu-Hsuan Shen、Tzenge-Lien Shih
DOI:10.1016/j.tet.2017.06.033
日期:2017.8
During the reaction course, we obtained not only the target azachalcones, but also penta-substituted cyclohexanols, which are seldom reported in the literatures. The formation of penta-substituted cyclohexanols was dependent on equivalents of base used and reaction time. Their formation followed a tandem reaction: Claisen-Schmidt condensation, three Michael reactions, retro-aldol reaction, and intramolecular
Cinchona alkaloid derived squaramide catalyzed diastereo- and enantioselective Michael addition of isocyanoacetates to 2-enoylpyridines
作者:Mei-Xin Zhao、Guang-Yu Zhu、Xiao-Li Zhao、Min Shi
DOI:10.1016/j.tet.2019.01.024
日期:2019.3
An efficient organocatalytic diastereo- and enantioselective Michael addition of α-substituted isocyanoacetates to 2-enoylpyridines catalyzed by cinchona alkaloid-derived squaramide has been achieved, affording the corresponding adducts with two adjacent tertiary-quaternary stereocenters in excellent yields (up to 99%) and good to excellent stereoselectivities (up to >20:1 dr, up to 98% ee) under mild
Solvent-free enantioselective conjugate addition and bioactivities of nitromethane to Chalcone containing pyridine
作者:Guoping Zhang、Chun Zhu、Dengyue Liu、Jianke Pan、Jian Zhang、Deyu Hu、Baoan Song
DOI:10.1016/j.tet.2016.11.063
日期:2017.1
catalysts in the enantioselective Michael additions of nitromethane to α,β-unsaturated ketones containing pyridine. The best results were obtained with the bifunctional catalyst prepared from 3,5-di(trifluoromethyl)-aniline under solvent-free conditions. This thiourea promoted the reaction with high enantioselectivities and chemical yields for aryl ketones. The origins of enantioselectivity were further