Ni-Catalyzed Carboxylation of C(sp<sup>2</sup>)– and C(sp<sup>3</sup>)–O Bonds with CO<sub>2</sub>
作者:Arkaitz Correa、Thierry León、Ruben Martin
DOI:10.1021/ja410883p
日期:2014.1.22
an excellent chemoselectivity profile using air-, moisture-insensitive and easy-to-handle nickel precatalysts. Our results render our method a powerful alternative, practicality and novelty aside, to commonly used organic halides as counterparts in carboxylation protocols. Furthermore, this study shows, for the first time, that traceless directing groups allow for the reductive coupling of substrates
近年来,芳基卤化物和苄基卤化物与 CO2 的羧化取得了重大进展,成为使用化学计量量明确的金属物质的方便替代品。然而,这些过程中的大多数都需要使用自燃和空气敏感试剂,目前的方法主要限于有机卤化物。因此,非常希望发现一种温和的、操作简单的替代羧化反应,该羧化反应在广泛的底物范围内使用容易获得的偶联伙伴发生。在此,我们报告了一种新的协议,该协议涉及 CO2 协同活化的开发和惰性 C(sp(2))-O 和 C(sp(3))-O 键的相当具有挑战性的活化,这些键源自简单且廉价的酒精,这是该领域以前未被认识到的机会。这种前所未有的羧化事件的特点是其简单、温和的反应条件、显着的选择性模式以及使用对空气、水分不敏感且易于处理的镍预催化剂的优异化学选择性曲线。我们的结果使我们的方法成为一种强大的替代方案,实用性和新颖性,可以替代常用的有机卤化物作为羧化方案中的对应物。此外,这项研究首次表明,无痕导向基团允许在没有扩展
Development and Mechanistic Studies of Iron-Catalyzed Construction of Csp<sup>2</sup>–B Bonds via C–O Bond Activation
Herein we describe an iron-catalyzed borylation of alkenyl and arylcarbamatesthrough the activation of a C–O bond. This protocol exhibits high efficiency, a broad substrate scope, and the late-stage borylation of biorelevant compounds, thus providing potential applications in medicinal chemistry. Moreover, this method enables orthogonal transformations of phenol derivatives and also offers good opportunities
在本文中,我们描述了通过C-O键的活化,铁催化的烯基和芳基氨基甲酸酯的硼酸酯化反应。该方案显示出高效率,广泛的底物范围以及生物相关化合物的后期硼化,因此在药物化学中提供了潜在的应用。而且,该方法能够使酚衍生物进行正交转化,并且还为合成多取代的芳烃提供了良好的机会。初步的机理研究表明,通过自由基途径的Fe II / Fe III催化循环可能与反应有关。
Nickel-Catalyzed Amination of Aryl Pivalates by the Cleavage of Aryl CO Bonds
作者:Toshiaki Shimasaki、Mamoru Tobisu、Naoto Chatani
DOI:10.1002/anie.200907287
日期:2010.4.6
Catalytic amination: The title reaction demonstrates the use of aryl carboxylates as suitable electrophilic coupling substrates in catalytic amination reactions. N‐heterocyclic carbene ligands and NaOtBu promote the amination of aryl pivalates through the cleavage of normally unreactive aryl carbon–oxygen bonds (see scheme; cod=cyclooctadiene).
催化胺化:标题反应表明在催化胺化反应中使用芳基羧酸盐作为合适的亲电子偶联底物。N-杂环卡宾配体和NaO t Bu通过裂解通常不活泼的芳基碳氧键来促进新戊酸芳基的胺化(参见方案; cod =环辛二烯)。
Nickel-Catalyzed α-Arylation of Ketones with Phenol Derivatives
The nickel‐catalyzed α‐arylation of ketones with readily available phenolderivatives (esters and carbamates) provides access to useful α‐arylketones. For this transformation, 3,4‐bis(dicyclohexylphosphino)thiophene (dcypt) was identified as a new, enabling, air‐stable ligand for this transformation. The intermediate of an assumed CO oxidative addition was isolated and characterized by X‐ray crystal‐structure
Ni‐catalyzed decarboxylative cross‐coupling of potassium polyfluorobenzoates with unactivated phenol and phenylmethanol derivatives is described. This novel transformation provides a practical and efficient protocol towards the synthesis of important polyfluorobiaryls and polyfluorinated diarylmethanes, and greatly enlarges the range of electrophiles utilized in decarboxylative coupling. Remarkably, preliminary