Mild Negishi Cross-Coupling Reactions Catalyzed by Acenaphthoimidazolylidene Palladium Complexes at Low Catalyst Loadings
作者:Zelong Liu、Ningning Dong、Mizhi Xu、Zheming Sun、Tao Tu
DOI:10.1021/jo400803s
日期:2013.8.2
3a exhibited extremely high catalytic activity toward Negishicross-coupling of alkylzinc reagents with a wide range of (hetero)arylhalides under mild reaction conditions within 30 min. Besides a great number of bromoarenes, various less expensive and inactive (hetero)aryl chlorides were coupled successfully with the alkyl- and arylzincreagents, in which active functional groups (such as -NH2) were
考虑到衍生自π-延伸的咪唑鎓盐的亚烷基的强大的σ-供体性质有利于提高所得钯N-杂环卡宾配合物的催化活性,因此制备了具有健壮的并咪唑-亚烷基钯配合物3a - c,具有不同的大取代基团通过在纯净的3-氯吡啶中与PdCl 2和K 2 CO 3加热,从相应的啶咪唑氯化物中得到满意的收率。即使在催化剂负载量低至0.25 mol%的情况下,配合物3a在温和的反应条件下,在30分钟内显示出对烷基锌试剂与各种(杂)芳基卤化物的Negishi交叉偶联极高的催化活性。除了大量的溴代芳烃外,还成功地将各种较便宜且不活泼的(杂)芳基氯化物与烷基-和芳基锌试剂偶联,其中具有活性官能团(例如-NH 2))即使在无保护的一锅双偶转换中也具有良好的耐受性。此外,在与仲烷基锌试剂偶联的情况下,有效抑制了导致异构化的线性产物的不希望的β-氢化物消除。通过杂芳基锌试剂和杂环氯代芳烃的偶联,该催化剂体系还显示出在杂二芳基结构方面
Ceramic boron carbonitrides for unlocking organic halides with visible light
作者:Tao Yuan、Meifang Zheng、Markus Antonietti、Xinchen Wang
DOI:10.1039/d1sc01028j
日期:——
halides, with visible light irradiation. Cross-coupling of halides to afford new C–H, C–C, and C–S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C–X (carbon–halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only
Enhancing Metalating Efficiency of the Sodium Amide NaTMP in Arene Borylation Applications
作者:Leonie J. Bole、Andreu Tortajada、Eva Hevia
DOI:10.1002/anie.202204262
日期:2022.6.27
The non-nucleophilic amide NaTMP, in combination with PMDETA and B(OiPr)3 have allowed the deprotonative borylation of unactivated arenes under mild conditions. The study of its reaction pathway and the characterisation of the intermediates by X-Ray crystallography and 1H DOSY enabled the development of this protocol, which forms boronates in a direct and easy way, enabling Suzuki–Miyaura couplings
非亲核酰胺 NaTMP 与 PMDETA 和 B(O i Pr) 3结合,可以在温和条件下对未活化的芳烃进行去质子硼酸化。通过对其反应途径的研究以及通过 X 射线晶体学和1 H DOSY 对中间体进行表征,促成了该方案的开发,该方案以直接、简单的方式形成硼酸酯,使 Suzuki-Miyaura 偶联能够以有效的方式获得联芳基化合物。
Delineating the Role of Substituents on the Coordination Behavior of Aroylhydrazone Ligands in Pd
<sup>II</sup>
Complexes and their Influence on Suzuki–Miyaura Coupling in Aqueous Media
piperonal aroylhydrazone ligands (HL1–HL4) with [PdCl2(PPh3)2] in CH3OH and CHCl3 afforded four new Pd(II) complexes (1–4) featuring diverse coordination behaviors. These complexes 1–4 were fully characterized by elemental analyses, UV/Visible, FT‐IR and 1H/13C NMR spectra. The variant coordination modes of piperonal aroylhydrazone ligands with Pd(II) ion in these complexes were unambiguously confirmed