The catalytic regio- and enantioselective hydrocarboxylation of alkenes with carbon dioxide is a straightforward strategy to construct enantioenriched α-chiral carboxylic acids but remains a big challenge. Herein we report the first example of catalytic highly enantio- and site-selective remote hydrocarboxylation of a wide range of readily available unactivated alkenes with abundant and renewable CO2
烯烃与二氧化碳的催化区域和对映选择性加氢羧化是构建对映体富集的 α-手性羧酸的简单策略,但仍然是一个巨大的挑战。在此,我们报告了在 SaBOX/Ni 催化剂的温和条件下,利用丰富且可再生的 CO 2对各种容易获得的未活化烯烃进行高度对映和位点选择性远程加氢羧化的催化例子。这一成功的关键是利用手性 SaBOX 配体,它与镍结合,同时控制链行走和羧化的对映选择性。该方法以高产率和区域选择性和对映选择性直接提供一系列带有各种官能团的不同烷基链取代或苯并稠合的 α-手性羧酸。此外,通过从商业起始材料中简明合成抗血小板聚集药物( R )-吲哚布芬,证明了该方法的合成效用。
Structural requirements for substrate in highly enantioselective hydrogenation over the cinchonidine-modified Pd/C
Relationship between substrate Structure and enantioselectivity is studied for the asymmetric hydrogenation of 42 different (E)-alpha, beta-disubstituted acrylic acids (propenoic acids) over cinchonidine-modified Pd/C. The beta-phenyl group is indispensable for high enantioselectivity of alpha-phenylcinnamic acid (2,3-diphenylpropenoic acid, 81% ee), and substitution on this group affects markedly the selectivity. The high ee up to 92% was achieved by the beta-p-alkoxyphenyl substitution, and the selectivity is ascribed mainly to stronger interaction of the substrate with the chiral modifier on the catalyst surface. In contrast, substitution on the alpha-phenyl group does not affect notably the enantioselectivity (80-82% ee) or even the alpha-phenyl group itself is not indispensable but replaceable with a properly bulky group for the high enantioselectivity, (C) 2008 Elsevier Inc. All rights reserved.
Palladium-Catalyzed Allylic Cross-Coupling Reactions of Primary and Secondary Homoallylic Electrophiles
作者:Benjamin J. Stokes、Susanne M. Opra、Matthew S. Sigman
DOI:10.1021/ja305403s
日期:2012.7.18
cross-coupling of homoallylic tosylate substrates using boronic acids and pinacol esters is reported. The reaction uses 2-(4,5-dihydro-2-oxazolyl)quinoline (quinox) as a ligand and is performed at ambient temperature. The scope of the reaction is broad in terms of both the boronate transmetalating reagent and the substrate and includes secondary tosylates. Mechanistic studies support an alkene-mediated
Aminoacid-derivatized Cu (II) complexes: Synthesis, DNA interactions and in vitro cytotoxicity
作者:Rinky Singh、P. Rama Devi、Sharmita S. Jana、Ranjitsinh V. Devkar、Debjani Chakraborty
DOI:10.1016/j.jorganchem.2017.04.017
日期:2017.11
Two different series of copper complexes, [Cu(MFL)(FcAA)H2O] (C1-C4) and [Cu(MFL) (BzAA)H2O] (C5-C8), where FcAA = ferrocenyl amino acid mannich base conjugates and BzAA = benzaldehyde amino acid mannich base conjugates have been synthesized and characterized by spectroscopic methods. The complexes have been investigated for their interactions with DNA by employing fluorescence quenching measurements
两种不同系列的铜络合物[Cu(MFL)(FcAA)H 2 O](C1-C4)和[Cu(MFL)(BzAA)H 2 O](C5-C8),其中FcAA =二茂铁基氨基酸曼尼希碱结合物和BzAA =苯甲醛氨基酸曼尼希碱结合物已通过光谱法合成和表征。通过使用荧光猝灭测量,紫外可见光谱和DNA粘度测量研究了复合物与DNA的相互作用。从DNA结合研究获得的高结合常数(K b = 10 6 M -1)促使复合物在A549人肺癌细胞上进行体外细胞毒性测定(采用MTT测定)。IC 50发现本文获得的值低于A549细胞系的配体的值。复合物对A549肿瘤细胞的抗增殖作用与其细胞内摄取特性一致。细胞摄取研究表明复合物C1-C8进入细胞质并积聚在细胞核中。用DAPI染色观察到核形态快速变化。cr啶橙/溴化乙锭双重染色显示,大多数A549细胞在治疗后12小时内进入早期凋亡状态。此外,所有复合物均通过触发G0 /