Enantioselective Construction of Cyclopenta[<i>b</i>]indole Scaffolds via the Catalytic Asymmetric [3 + 2] Cycloaddition of 2-Indolylmethanols with <i>p</i>-Hydroxystyrenes
作者:Meng-Meng Xu、Hai-Qing Wang、Ying Wan、Shu-Liang Wang、Feng Shi
DOI:10.1021/acs.joc.7b01731
日期:2017.10.6
The catalyticasymmetric [3 + 2] cycloaddition of 2-indolylmethanols to p-hydroxystyrenes was established in the presence of a chiral phosphoramide, and this reaction provided chiral cyclopenta[b]indole scaffolds in generally high yields and with good enantioselectivities (up to 98% yield, 99:1 er). The control experiments demonstrated that the dual hydrogen-bonding activation mode of the chiral catalyst
在手性磷酰胺存在下,建立了2-吲哚基甲醇催化不对称[3 + 2]环加成对羟基苯乙烯的反应,该反应通常以高收率和良好的对映选择性提供手性环戊[ b ]吲哚骨架。收率99:1 er)。对照实验表明,手性催化剂对两种底物的双重氢键活化方式在反应中起重要作用。此外,大规模反应表明,该催化不对称的[3 + 2]环加成反应可扩大规模,用于合成手性环戊[ b ]吲哚衍生物。
[EN] PREPARING AN UNSATURATED CARBOXYLIC ACID SALT FROM AN ALKENE AND CARBON DIOXIDE USING A HETEROGENEOUS BASE<br/>[FR] PRÉPARATION D'UN SEL D'ACIDE CARBOXYLIQUE INSATURÉ À PARTIR D'UN ALCÈNE ET DE DIOXYDE DE CARBONE À L'AIDE D'UNE BASE HÉTÉROGÈNE
申请人:BASF SE
公开号:WO2015173296A1
公开(公告)日:2015-11-19
Process for preparing an α,β-ethylenically unsaturated carboxylic acid salt, comprising, reacting an alkene and carbon dioxide in the presence of a carboxylation catalyst to obtain a catalyst-coordinated carboxylated intermediate, treating the catalyst- coordinated carboxylated intermediate with a heterogeneous base, and releasing the α,β-ethylenically unsaturated carboxylic acid salt, wherein the heterogeneous base comprises an organic basic moiety that is immobilized on a solid support. The process avoids accumulation of the conjugate acid of the base in the reaction medium.
Vinylation of Unprotected Phenols Using a Biocatalytic System
作者:Eduardo Busto、Robert C. Simon、Wolfgang Kroutil
DOI:10.1002/anie.201505696
日期:2015.9.7
conditions to afford the corresponding para‐vinylphenolderivatives while releasing only one molecule of CO2 and water as the by‐products. This transformation was achieved by designing a biocatalytic system that combines three biocatalytic steps, namely the CC coupling of phenol and pyruvate in the presence of ammonia, which leads to the corresponding tyrosine derivative, followed by deamination and decarboxylation
LIQUID CRYSTAL COMPOSITION AND LIQUID CRYSTAL DISPLAY ELEMENT
申请人:Chisso Corporation
公开号:EP2116587A1
公开(公告)日:2009-11-11
A liquid crystal composition is provided that satisfies at least one characteristic among the characteristics such as a high maximum temperature of a nematic phase, a low minimum temperature of a nematic phase, a small viscosity, a large optical anisotropy, a large dielectric anisotropy, a large specific resistance, a high stability to ultraviolet light and a high stability to heat, or is properly balanced regarding at least two characteristics. An AM device is provided that has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth.
The liquid crystal composition having a nematic phase, wherein the first component contains a specific three ring compound having a large optical anisotropy, the second component contains a specific four ring compound having a large dielectric anisotropy, and the third component contains a specific two ring compound having an especially small viscosity. The liquid crystal display device contains the liquid crystal composition.
提供了一种液晶组合物,它至少满足向列相最高温度高、向列相最低温度低、粘度小、光学各向异性大、介电各向异性大、比电阻大、对紫外线稳定性高和对热稳定性高等特性中的一个特性,或者至少在两个特性上达到适当平衡。所提供的 AM 设备具有响应时间短、电压保持比大、对比度大、使用寿命长等特点。
具有向列相的液晶组合物,其中第一组分包含具有较大光学各向异性的特定三环化合物,第二组分包含具有较大介电各向异性的特定四环化合物,第三组分包含具有特别小粘度的特定二环化合物。液晶显示装置包含液晶组合物。