Iron-catalyzed asymmetric hydrosilylation of ketones
作者:Ziqing Zuo、Lei Zhang、Xuebing Leng、Zheng Huang
DOI:10.1039/c5cc00612k
日期:——
iminopyridine-oxazoline (IPO) ligands have been synthesized. The most sterically hindered iron catalyst exhibits excellent activity (up to 99% yield) and high enantioselectivity (up to 93% ee) in asymmetrichydrosilylation of aryl ketones.
The synthesis of a new paracyclophane phosphine is described. This ligand was highly efficient in the ruthenium-catalyzed asymmetric hydrogenation of various aromatic and heteroaromatic ketones.
描述了一种新的对环烷膦的合成。该配体在钌催化的各种芳族和杂芳族酮的不对称氢化中非常有效。
The Palladium-Catalyzed Aerobic Kinetic Resolution of Secondary Alcohols: Reaction Development, Scope, and Applications
作者:Davidâ C. Ebner、Jeffreyâ T. Bagdanoff、Ericâ M. Ferreira、Ryanâ M. McFadden、Danielâ D. Caspi、Raissaâ M. Trend、Brianâ M. Stoltz
DOI:10.1002/chem.200902172
日期:2009.12.7
and tert‐butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23 °C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kineticresolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good‐to‐excellent
已经开发出第一个钯催化的仲醇对映选择性氧化反应,利用容易获得的二胺(-)-金雀花石作为手性配体,分子氧作为化学计量氧化剂。关于碱基和氢键供体作用的机制见解导致了对原始系统的一些改进。也就是说,碳酸铯和叔丁醇的添加大大提高了反应速率,促进了快速分辨率。使用氯仿作为溶剂允许在 23 °C 下使用环境空气作为终端氧化剂,从而提高催化剂选择性。这些改进的反应条件使得能够以良好至优异的选择性因子成功地将苄基、烯丙基和环丙基仲醇动力学拆分为高对映体过量。该催化剂体系也已应用于内消旋二醇的去对称化,提供高产率的对映体富集的羟基酮。
Nickel-Catalyzed Borylation of Benzylic Ammonium Salts: Stereospecific Synthesis of Enantioenriched Benzylic Boronates
作者:Corey H. Basch、Kelsey M. Cobb、Mary P. Watson
DOI:10.1021/acs.orglett.5b03455
日期:2016.1.4
stereospecific, nickel-catalyzed cross-coupling of secondarybenzylic ammonium salts and diboronate esters to deliver highly enantioenriched benzylic boronates. This reaction utilizes amine-derived electrophiles, which are readily available in high enantiopurity, and simple, inexpensive nickel catalysts. This reaction has broad scope, enabling synthesis of a variety of secondarybenzylic boronates in
Benzimidazoles as Ligands in the Ruthenium-Catalyzed Enantioselective Bifunctional Hydrogenation of Ketones
作者:Jeremy M. Praetorius、Ruiyao Wang、Cathleen M. Crudden
DOI:10.1021/om900897b
日期:2010.2.8
ligands bound to the ruthenium center are active for the mild and chemoselective hydrogenation of ketones in the presence of alkenes. Catalysts that exist as a single diastereomer, prepared with enantiomerically pure diphosphanes, catalyze the hydrogenation of prochiral ketones with moderate levels of enantioselectivity that are significantly improved relative to catalysts existing in several conformations
L = N的一系列Cl 2 Ru(diphosphane)L 2(II)配合物已经合成并表征了通过氮键与金属键合的1-烷基化苯并咪唑。对于1-甲基苯并咪唑,所得络合物以所有可能的构象异构体的统计混合物形式存在。当苯并咪唑上的取代基的大小增加到10时,可以制备出以单一非对映异构体形式存在的络合物。所有具有结合到钌中心的苯并咪唑配体的配合物在烯烃存在下对酮的轻度和化学选择性氢化均具有活性。用对映体纯的二膦制备的以单一非对映异构体形式存在的催化剂以中等对映体选择性催化前手性酮的氢化,相对于以几种构象存在的催化剂,该手性酮的氢化显着提高。