两种常见受保护形式的胺(氨基甲酸酯和磺酰胺)在 Ni 催化的 Suzuki 反应中作为导向基团的能力已被用于开发用于交叉偶联未活化烷基亲电子试剂的催化不对称方法。在市售镍配合物和手性配体存在下,外消旋仲溴化物和氯化物在室温下以良好的 ee 立体收敛过程中形成 CC 键。旨在阐明与 Ni(氨基甲酸酯和磺酰胺的氧)结合的位点的结构对映选择性研究导致发现,砜也可用作外消旋烷基卤化物的不对称 Suzuki 交叉偶联的有用导向基团。据我们所知,这项研究提供了在金属催化的不对称 CC 键形成反应中使用磺酰胺或砜作为有效导向基团的第一个例子。一项机理研究表明,金属转移发生时保留了立体化学,并且由此产生的 Ni-C 键在催化循环的后续阶段不会发生均裂。
Asymmetric Alkyl−Alkyl Cross-Couplings of Unactivated Secondary Alkyl Electrophiles: Stereoconvergent Suzuki Reactions of Racemic Acylated Halohydrins
作者:Nathan A. Owston、Gregory C. Fu
DOI:10.1021/ja105924f
日期:2010.9.1
A method for asymmetric alkyl-alkylSuzuki reactions of unactivatedsecondaryalkyl electrophiles, specifically, cross-couplings of racemic acylated halohydrins with alkylborane reagents, has been developed. A range of protected bromohydrins, as well as a protected chlorohydrin and a homologated bromohydrin, are coupled in good ee by a catalyst derived from commercially available components.
已开发出一种用于未活化仲烷基亲电试剂的不对称烷基-烷基 Suzuki 反应的方法,特别是外消旋酰化卤代醇与烷基硼烷试剂的交叉偶联。一系列受保护的溴醇,以及受保护的氯醇和同系溴醇,通过衍生自市售组分的催化剂以良好的 ee 偶联。
Nickel-Catalyzed Alkoxy-Alkyl Interconversion with Alkylborane Reagents through C−O Bond Activation of Aryl and Enol Ethers
A nickel‐catalyzed alkylation of polycyclic aromatic methyl ethers as well as methyl enol ethers with B‐alkyl 9‐BBN and trialkylborane reagents that involves the cleavage of stable C(sp2)−OMe bonds is described. The transformation has a wide substrate scope and good chemoselectivity profile while proceeding under mild reaction conditions; it provides a versatile way to form C(sp2)−C(sp3) bonds that
Direct Synthesis of Ketones from Methyl Esters by Nickel‐Catalyzed Suzuki–Miyaura Coupling
作者:Yan‐Long Zheng、Pei‐Pei Xie、Omid Daneshfar、Kendall N. Houk、Xin Hong、Stephen G. Newman
DOI:10.1002/anie.202103327
日期:2021.6.7
direct conversion of alkyl esters to ketones has been hindered by the sluggish reactivity of the starting materials and the susceptibility of the product towards subsequent nucleophilic attack. We have now achieved a cross-coupling approach to this transformation using nickel, a bulky N-heterocyclic carbene ligand, and alkyl organoboron coupling partners. 65 alkylketonesbearing diverse functional groups
烷基酯向酮的直接转化受到起始材料缓慢的反应性和产物对随后亲核攻击的敏感性的阻碍。我们现在已经使用镍、一种庞大的 N-杂环卡宾配体和烷基有机硼偶联伙伴实现了这种转化的交叉偶联方法。用这种方法合成了 65 个带有不同官能团和杂环支架的烷基酮。对于带有易于被 Ni 裂解的其他键的多功能底物的 C(酰基)-O 键活化,观察到催化剂控制的化学选择性,包括芳醚、芳基氟和 N-Ph 酰胺官能团。密度泛函理论计算为 Ni 0 /Ni II提供了机械支持 催化循环,并证明稳定的大催化剂和底物之间的非共价相互作用对反应的成功至关重要。
Synthesis of Isomerically Pure (<i>Z</i>)-Alkenes from Terminal Alkynes and Terminal Alkenes: Silver-Catalyzed Hydroalkylation of Alkynes
作者:Mitchell T. Lee、Madison B. Goodstein、Gojko Lalic
DOI:10.1021/jacs.9b09336
日期:2019.10.30
molecules and often are used as intermediates in organic synthesis. Many alkenes exist in two stereoisomeric forms (E and Z), which have different structures and different properties. The selective formation of the two isomers is an important synthetic goal that has long inspired the development of new synthetic methods. However, the efficient synthesis of diastereopure, thermodynamically less stable, Z-alkenes
Alkyl-Alkyl Suzuki Cross-Coupling of Unactivated Secondary Alkyl Chlorides
作者:Zhe Lu、Gregory C. Fu
DOI:10.1002/anie.201003272
日期:2010.9.3
reaction designed specifically for the title substrates CC coupling with alkyl boranes occurred in good yield at room temperature with commercially available catalyst components (see scheme). This versatile method is also suitable for Suzuki reactions of secondary and primary alkyl bromides and iodides, as well as primary alkylchlorides.
没有问题基材之类的东西!在专门为标题底物设计的反应中,C C 与烷基硼烷偶联,在室温下使用市售催化剂组分以良好的产率发生(参见方案)。这种通用方法也适用于仲和伯烷基溴化物和碘化物以及伯烷基氯化物的 Suzuki 反应。