Highly enantioselective routes to darzens and acetate aldol products from achiral aldehydes and t-butyl bromoacetate
摘要:
New methodology is described for the enantioselective coupling of t-butyl bromoacetate with aldehydes to give anti-alpha-bromo beta-hydroxy esters (1), useful precursors of chiral glycidic esters (2), acetate aldols (3), beta-amino acid esters (4) and alpha-amino acid esters (5).
Asymmetric dehydration of β-hydroxy esters and application to the syntheses of flavane derivatives
作者:Eui Ta Choi、Min Hee Lee、Yongtae Kim、Yong Sun Park
DOI:10.1016/j.tet.2007.11.026
日期:2008.2
Catalytic asymmetricdehydration of β-aryl or alkyl substituted β-hydroxyesters via kineticresolution has been investigated. A brief survey of 10 different chiral ligands is conducted to examine the effects of chiral ligand structure on selectivity of the dehydration. The kineticresolution of a variety of rac-β-hydroxy tert-butyl esters in the presence of prolinol chiral ligand 2 and BrZnCH2CO2-t-Bu
已经研究了通过动力学拆分对β-芳基或烷基取代的β-羟基酯进行催化不对称脱水的方法。简要调查了10种不同的手性配体,以研究手性配体结构对脱水选择性的影响。在脯氨醇手性配体2和BrZnCH 2 CO 2 - t -Bu存在下,多种rac -β-羟基叔丁酯的动力学拆分可提供高度对映体富集的β-羟基酯14 – 21,选择性因子为11至66.此外,这种不对称合成方法在制备对映体富集的黄烷衍生物中的应用演示了25 – 29。
Asymmetric dehydration of β-hydroxy esters via kinetic resolution
作者:Yongtae Kim、Eui Ta Choi、Min Hee Lee、Yong Sun Park
DOI:10.1016/j.tetlet.2007.02.111
日期:2007.4
Catalytic asymmetricdehydration of β-hydroxyesters via kineticresolution has been investigated. The kineticresolution of rac-β-hydroxy esters in the presence of prolinol chiral ligand 2a and BrZnCH2CO2t-Bu can provide highly enantioenriched β-hydroxyesters 3 and 5–11 with selectivity factors ranging from 15 to 42.
已经研究了通过动力学拆分对β-羟基酯进行催化不对称脱水的方法。的动力学拆分外消旋-β-羟基酯在存在脯氨醇手性配体2A和BrZnCH 2 CO 2吨-Bu能够提供对映体富集的高度β羟基酯3和5 - 11有选择性因素,从15至42。