Facile preparation of aromatic esters from aromatic bromides with ethyl formate or DMF and molecular iodine via aryllithium
作者:Sousuke Ushijima、Katsuhiko Moriyama、Hideo Togo
DOI:10.1016/j.tet.2012.04.016
日期:2012.6
Various aromatic bromides were treated with n-BuLi and subsequently with ethyl formate, followed by the reaction with ethanol and molecular iodine in the presence of K2CO3 to provide the corresponding aromatic ethyl esters in good yields. Moreover, aromatic bromides could be transformed into the corresponding aromatic methyl esters in good yields by the treatment with n-BuLi and subsequently with DMF
各种芳族溴化物先用n- BuLi处理,然后再用甲酸乙酯处理,然后在K 2 CO 3存在下与乙醇和分子碘反应,以高收率提供相应的芳族乙基酯。此外,通过用n- BuLi和随后用DMF处理,然后与甲醇,分子碘和K 2 CO 3反应,可以将芳族溴化物以良好的产率转化成相应的芳族甲基酯。通过用n处理,一些芳族化合物也可以高收率转化为相应的芳族酯。-BuLi,然后与甲酸乙酯或DMF进行反应,然后与分子碘和K 2 CO 3反应。本反应为无过渡金属,无一氧化碳的因此为芳族溴化物和芳族化合物到芳族酯的环境友好的一锅转化提供了新颖的途径。
Catalytic C-F Bond Activation of Perfluoroarenes by Tricoordinated Gold(I) Complexes
作者:Jin-Hui Zhan、Hongbin Lv、Yi Yu、Jun-Long Zhang
DOI:10.1002/adsc.201100843
日期:2012.5.21
We report the first example of gold catalyzing CF bondactivation for perfluoroarenes in the presence of silanes. Tricoordinated gold(I) complexes supported by Xantphos‐type ligands, such as Xantphos and tBuXantphos ligands, exhibit efficacy in the hydrodefluorination (HDF) of various types of perfluoroarenes. For [tBuXantphosAu(AuCl2)], the highest turnover number is up to 1000 in the HDF of pen
我们报告了在硅烷存在下金催化全氟芳烃的CF键活化的第一个例子。Xantphos型配体(如Xantphos和t BuXantphos配体)支持的三配位金(I)络合物在各种类型的全氟芳烃的加氢脱氟(HDF)中显示出功效。对于[ t BuXantphosAu(AuCl 2)],在五氟硝基苯与二苯基硅烷的HDF中,最高周转数高达1000。对官能团耐受性的检查表明,该金(I)催化方案与酮,酯,羧酸盐,炔基,烯基和酰胺基团正交,表明其在化学选择性C中的潜在应用F激活。机理研究表明,四配位的[L 2 Au] +和[LAu] +之间的平衡对于金催化剂的反应性很重要,这取决于Xantphos型配体的空间庞大基团。此外,对可能的反应路径的计算研究表明,金(I)阳离子直接氧化CF键可能是这些催化反应中的关键步骤。
“π-Hole−π” Interaction Promoted Photocatalytic Hydrodefluorination via Inner-Sphere Electron Transfer
作者:Jingzhi Lu、Navneet S. Khetrapal、Jacob A. Johnson、Xiao Cheng Zeng、Jian Zhang
DOI:10.1021/jacs.6b08620
日期:2016.12.14
promotes the electron transfer against unfavorable energetics (ΔGET up to 0.63 eV) and initiates the subsequent HDF. The sterichindrance of Py and FA largely dictates the HDF reaction rate, pointing to an inner-sphere electron transfer pathway. This work highlights the importance of the size and shape of the photocatalyst and the substrate in controlling the electron transfermechanism and rates as well
我们描述了使用芘基光催化剂 (Py) 的多氟芳烃 (FA) 的无金属光催化加氢脱氟 (HDF)。Py 和 FA 之间微弱的“π-空穴-π”相互作用促进了针对不利能量的电子转移(ΔGET 高达 0.63 eV)并启动随后的 HDF。Py 和 FA 的空间位阻在很大程度上决定了 HDF 反应速率,指向内部球体电子转移途径。这项工作强调了光催化剂和基材的尺寸和形状在控制电子转移机制和速率以及整个光催化过程中的重要性。
Diazaphospholene-Catalyzed Hydrodefluorination of Polyfluoroarenes with Phenylsilane via Concerted Nucleophilic Aromatic Substitution
The metal-free catalytic C–F bond activation of polyfluoroarenes was achieved with diazaphospholene as the catalyst and phenylsilane as the terminal reductant. Density functional theory calculations suggested a concerted nucleophilic aromatic substitution mechanism.
Regioselective ortho-hydrodefluorination of pentafluorobenzoic acid by low-valent nickel complexes
作者:N.Yu Adonin、V.F Starichenko
DOI:10.1016/s0022-1139(99)00181-5
日期:2000.1
2,3,4,5-Tetrafluorobenzoic and 3,4,5-trifluorobenzoic acids were prepared in high yields by reaction of C6F5COOH with zinc in the presence of NiCl2–2′-bipyridine (or 1,10-phenanthroline) complexes.