在5 bar H 2下,使用RuPHOX-Ru作为手性催化剂,对各种α-取代的丙烯酸进行不对称氢化,从而以高达99%的收率和99.9%ee的产率提供相应的手性α-取代的丙酸。该反应可以以克级进行,具有相对较低的催化剂负载量(最高5000 S / C),所得产物(97%,99.3%ee)可用作构建生物活性手性分子的关键中间体。该不对称方案已成功应用于二氢青蒿酸的不对称合成,这是抗疟疾药物青蒿素工业合成所需的关键中间体。
of carboxylic acids. Herein, we reported the development of a palladium-catalyzed highly enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water. A monodentate phosphoramidite ligand L6 plays vital role in the reaction. The reaction tolerates a range of functional groups, and provides a facile and atom-economical approach to an array of 2-arylpropanoic acids including several
不对称羟基羰基化是合成羧酸的最基本但最具挑战性的方法之一。在此,我们报道了钯催化的乙烯基芳烃与 CO 和水的高度对映选择性马尔可夫尼科夫羟基羰基化的发展。单齿亚磷酰胺配体L6反应中起重要作用。该反应耐受一系列官能团,并为一系列 2-芳基丙酸(包括几种常用的非甾体抗炎药)提供了一种简便且原子经济的方法。该催化体系还使乙烯基芳烃与醇发生不对称马尔科夫尼科夫氢烷氧基羰基化反应,得到 2-芳基丙酸酯。机理研究表明,氢化钯是不可逆的,是区域和对映体决定步骤,而水解/醇解可能是限速步骤。
Highly Enantioselective Hydroxycarbonylation and Alkoxycarbonylation of Alkenes using Dipalladium Complexes as Precatalysts
作者:Tina M. Konrad、José A. Fuentes、Alexandra M. Z. Slawin、Matthew L. Clarke
DOI:10.1002/anie.201004415
日期:2010.11.22
Joined at Pd: Novel palladium catalysts like 1, in which the planar‐chiral phosphine acts as a bridging ligand, have been developed. These dimetallic complexes are highlyenantioselective catalysts in the hydroxycarbonylation of alkenes, a reaction that has proven problematic over the years. PTSA=para‐toluenesulfonic acid.
Simultaneous control of regioselectivity and enantioselectivity in the hydroxycarbonylation and methoxycarbonylation of vinyl arenes
作者:Tina M. Konrad、Jamie T. Durrani、Christopher J. Cobley、Matthew L. Clarke
DOI:10.1039/c3cc41291a
日期:——
Using a family of novel mononuclear and dinuclear palladium complexes of phanephos ligands, the simultaneous control of regioselectivity and enantioselectivity in the hydroxycarbonylation and alkoxycarbonylation of styrene derivatives has been realised for the first time.
(ee up to 99%, TON up to 20 000) for the asymmetric hydrogenation of both 2-aryl and 2-alkyl acrylic acids through ion pair noncovalent interaction under base free and mild reaction conditions. Well-known anti-inflammatory drugs such as naproxen and ibuprofen together with the intermediate for the preparation of Roche ester and some bioactive compounds were also efficiently obtained with excellent ee