Enantiomeric recognition of organic ammonium salts by chiral dialkyl-, dialkenyl-, and tetramethyl-substituted pyridino-18-crown-6 and tetramethyl-substituted bispyridino-18-crown-6 ligands: comparison of temperature-dependent proton NMR and empirical force field techniques
cations and the catalytic activity of Pr(OTf)(3)-crown ether complexes. From X-ray structures of RE(NO(3))(3)-crown ether complexes, it was found that they had similar structures regardless of the RE cations and the crown ethers used. Accordingly, the binding ability of the crown ether with the RE cation and the catalytic activity of the complex are important for attaining high selectivity in the asymmetric
使用 Pr(OTf)(3) 和手性 bis-pyridino-18-crown-6 开发了水性介质中的催化不对称醛醇反应 1. 在使用稀土金属三氟甲磺酸盐 (RE(OTf)(3)) 的不对称醛醇反应中和1,金属阳离子的离子直径的微小变化极大地影响了产物的非对映选择性和对映选择性。冠醚吡啶环4位的取代基(MeO、Br)对不对称醛醇反应的选择性没有显着影响,尽管它们影响了冠醚与RE阳离子的结合能力和催化活性。 Pr(OTf)(3)-冠醚配合物。从 RE(NO(3))(3)-冠醚配合物的 X 射线结构中,发现它们具有相似的结构,无论使用的 RE 阳离子和冠醚如何。因此,冠醚与稀土阳离子的结合能力和配合物的催化活性对于在不对称醛醇反应中获得高选择性很重要。衍生自酮和硫酯的各种芳香族和 α,β-不饱和醛和甲硅烷基烯醇醚可用于使用 Pr(OTf)(3) 和 1 的催化不对称醛醇反应,以提供良好至高产率
Enantiomeric recognition of organic ammonium salts by chiral dialkyl-, dialkenyl-, and tetramethyl-substituted pyridino-18-crown-6 and tetramethyl-substituted bispyridino-18-crown-6 ligands: comparison of temperature-dependent proton NMR and empirical force field techniques
作者:Jerald S. Bradshaw、Peter Huszthy、Christopher W. McDaniel、Cheng Y. Zhu、N. Kent Dalley、Reed M. Izatt、Shneior Lifson