Chiral [RuCl2(dipyridylphosphane)(1,2-diamine)] Catalysts: Applications in Asymmetric Hydrogenation of a Wide Range of Simple Ketones
作者:Jing Wu、Jian-Xin Ji、Rongwei Guo、Chi-Hung Yeung、Albert S. C. Chan
DOI:10.1002/chem.200204688
日期:2003.7.7
The dipyridylphosphane/diamine-Ru complex combined with tBuOK in 2-propanol acts as a very effective catalyst system for the enantioselective hydrogenation of a diverse range of simple ketones including heteroaromatic ketones, substituted benzophenones, alkenyl ketones, and cyclopropyl ketones. The combination of desirable features, such as quantitative chemical yields within hours, broad substrate
Dynamic Processes in the Copper-Catalyzed Substitution of Chiral Allylic Acetates Leading to Loss of Chiral Information
作者:Jakob Norinder、Jan-E. Bäckvall
DOI:10.1002/chem.200601684
日期:2007.5.7
formation. Equilibration of the reaction intermediates is of importance for a possible development of a dynamickineticasymmetrictransformation (DYKAT) process, in which a chiral catalyst is used to produce an optically active product from a racemicsubstrate, by means of a dynamic equilibrium of the diastereomeric reaction intermediates.
conditions for 2 h with less than 35% oxidation of the DNA chain. An assay measuring the diastereo- and enantioselectivity of the photosensitized enereaction of mesitylol with singletoxygen was set up that provides diastereomeric ratios via NMR of aliquots of the reaction solution. Enantiomers were separated gas chromatographically on a chiral stationary phase and were assigned based on the product distribution
DNA介导的纳米结构的最新发展为新型反应中心的发展铺平了道路。作为卟啉催化反应的纳米结构反应中心项目的一部分,我们开发了四(对羟基苯基)卟啉-寡核苷酸杂化物的固相合成。在这些杂合体中,多达四个核酸链通过磷酸二酯键与卟啉的酚取代基相连。发现具有 TTAA 序列的一条寡核苷酸链的代表性杂种在有氧条件下可在光照射下存活 2 小时,且 DNA 链的氧化低于 35%。建立了一种测定异丙醇与单线态氧的光敏烯反应的非对映选择性和对映选择性的测定法,该测定法通过反应溶液等分试样的 NMR 提供非对映异构体比率。对映异构体在手性固定相上进行气相色谱分离,并根据对映异构体富集的起始材料获得的产物分布进行分配。我们的结果是探索基于 DNA 和卟啉的纳米结构反应介质的起点。
Asymmetric Hydrogenation of Alkenyl, Cyclopropyl, and Aryl Ketones. RuCl<sub>2</sub>(xylbinap)(1,2-diamine) as a Precatalyst Exhibiting a Wide Scope
Asymmetric hydrogenation of α,β-unsaturated ketones catalyzed by Ru–TPPTS–(S,S)-DPENDS complex in ionic liquids
作者:Jinbo Wang、Ruixiang Qin、Haiyan Fu、Jun Chen、Jian Feng、Hua Chen、Xianjun Li
DOI:10.1016/j.tetasy.2007.03.021
日期:2007.4
The asymmetric hydrogenation of alpha,beta-unsaturated ketones catalyzed by the achiral ruthenium monophosphine complex RuCl2(TPPTS)(2) [TPPTS: P(m-C6H4SO3Na)(3)] modified by (S,S)-DPENDS [disodium salt of sulfonated (S,S)-1,2-diphenyl-1,2-ethylene-diamine] was investigated in ionic liquid [RMIM]Ts (1-alkyl-3-methytimidazolium p-methylphenylsulfonates, R = ethyl, butyl, octyl, dodecyl). Chemoselectivity of 100% and 75.9% ee were obtained for benzalacetone under the optimized conditions. The resulting products can be easily separated from the catalyst immobilized in ionic liquid [EMIM]Ts by extraction with n-hexane, while the catalyst can be reused seven times without the loss of catalytic activity and enantio selectivity. Especially, the addition of water can improve the performance of the catalyst. (c) 2007 Elsevier Ltd. All rights reserved.