合成了空气和湿气稳定的双(二咪唑基吡啶)镍(II)配合物([[(diNHC)2 Ni] 2+)3a,b及其相应的银(I)4a,b和钯(II)5a,b配合物并通过NMR和单晶X射线分析进行表征。在Mizoroki–Heck和Suzuki–Miyaura偶联反应中评估了复合物3a的催化潜能。在Suzuki-Miyaura偶联反应中,镍预催化剂3a对芳基氯化物和芳基氟化物的偶联具有活性。类似合成的Pd(II)配合物导致形成(diNHC)PdCl 2物种,该物种对芳基氟化物的偶联没有活性。对于Mizoroki-Heck反应,发现当使用Na 2 CO 3或NEt 3作为碱时,在没有镍或钯预催化剂的情况下,芳基碘化物可以被活化,而在Suzuki-Miyaura反应中芳基碘化物和芳基溴化物可以被活化。 K 3 PO 4为碱时,无催化剂。
Dual Photoredox-/Palladium-Catalyzed Cross-Electrophile Couplings of Polyfluoroarenes with Aryl Halides and Triflates
作者:Jian Qin、Shengqing Zhu、Lingling Chu
DOI:10.1021/acs.organomet.0c00813
日期:2021.7.26
arylation of polyfluoroarenes with arylhalides and triflates in the presence of dialkylamines is reported for the first time. This synergistic protocol affords access to a series of fluorodiaryls from easily available starting materials under mild and operationally simple conditions. A series of mechanistic experiments, including the stoichiometric reactions of a ligated (aryl)Pd complex, Stern–Volmer fluorescence
Synthesis of unsymmetrical biaryl ethers through nickel-promoted coupling of polyfluoroarenes with arylboronic acids and oxygen
作者:Jian Zhang、Jingjing Wu、Yang Xiong、Song Cao
DOI:10.1039/c2cc33755j
日期:——
Polyfluoro-substituted unsymmetrical biaryl ethers were synthesized via a novel Ni-catalyzed cross-coupling reaction of polyfluoroarenes with arylboronic acids and oxygen. The polyfluorinated arenes presumably captured the phenoxide intermediate efficiently, which made the oxygen-insertion proceed smoothly via the SNAr protocol. The 18O labeling experiment demonstrated that the oxygen introduced into unsymmetrical diaryl ether originated from very trace amounts of oxygen in the reaction system. A plausible mechanism was also suggested.
Transition‐Metal‐Free Coupling of Polyfluorinated Arenes and Functionalized, Masked Aryl Nucleophiles
作者:Lucie Finck、Martin Oestreich
DOI:10.1002/chem.202101731
日期:2021.8.2
coupling of sufficiently electron-deficient fluorinatedarenes and functionalized N-aryl-N’-silyldiazenes as masked aryl nucleophiles is reported. The fluoride-promoted transformation involves the in situ generation of the aryl nucleophile decorated with various sensitive functional groups followed by a stepwise nucleophilic aromatic substitution (SNAr). These reactions typically proceed at room temperature
报道了足够缺电子的氟化芳烃和官能化的N-芳基-N'-甲硅烷基二氮烯作为掩蔽的芳基亲核试剂的化学选择性 C(sp 2 )-C(sp 2 ) 偶联。氟化物促进的转化涉及原位生成用各种敏感官能团修饰的芳基亲核试剂,然后逐步进行亲核芳族取代 (S N Ar)。这些反应通常在室温下在几分钟内进行。这种催化过程允许两个偶联伙伴的功能化,以良好的产率提供高度氟化的联芳基化合物。
Highly Selective Pd-Catalyzed Direct C–F Bond Arylation of Polyfluoroarenes
作者:Zhi-Ji Luo、Hai-Yang Zhao、Xingang Zhang
DOI:10.1021/acs.orglett.8b00692
日期:2018.5.4
A directing-group-free palladium-catalyzeddirectarylation of simple polyfluoroarenes with arylboronic acids through selective C–F bond activation is described. The combination of Pd(OAc)2 with BrettPhos was identified as an efficient catalytic system to promote the reaction with high regioselectivity and broad substrate scope. Preliminary mechanistic studies reveal that the oxidative addition of
Palladium-Catalyzed Coupling Reaction of Perfluoroarenes with Diarylzinc Compounds
作者:Masato Ohashi、Ryohei Doi、Sensuke Ogoshi
DOI:10.1002/chem.201303451
日期:2014.2.10
to promote the oxidative addition of one CF bond of C6F6 to palladium. Stoichiometric reactions revealed that an expected oxidative‐addition product, trans‐[Pd(C6F5)I(PCy3)2], generated from the reaction of [Pd(PCy3)2] with C6F6 in the presence of lithium iodide, was not involved in the catalytic cycle. Instead, a transient three‐coordinate, monophosphine‐ligated species, [Pd(C6F5)I(PCy3)], emerged
该报告描述了六氟苯(C 6 F 6)与二芳基锌化合物的首次Pd 0催化交叉偶联,得到了多种五氟苯基芳烃。该反应可以应用于其他全氟芳烃,例如八氟甲苯,五氟吡啶和全氟萘,以得到相应的多氟偶联产物。在该催化反应中的最佳配体是PCy 3,碘化锂作为偶联反应的添加剂是必不可少的。碘化锂在该催化反应中的作用之一是促进C 6 F 6的一个CF键的氧化加成。钯。化学计量反应表明,在存在条件下,[Pd(PCy 3)2 ]与C 6 F 6的反应产生了预期的氧化加成产物反式[Pd(C 6 F 5)I(PCy 3)2 ]。碘化锂的一部分不参与催化循环。取而代之的是,瞬态三配位单膦连接的物质[Pd(C 6 F 5)I(PCy 3)]出现为催化循环中的潜在中间体。因此,我们分离了一种新型的Pd II复合物[Pd(C 6 F 5)I(PCy3)(py)],其中吡啶(py)充当不稳定的配体以生成瞬态物质。实际上,在碘化锂的存在下,发现该Pd