Intermolecular C−H Activation of Hydrocarbons by Tungsten Alkylidene Complexes: An Experimental and Computational Mechanistic Study
作者:Craig S. Adams、Peter Legzdins、W. Stephen McNeil
DOI:10.1021/om010380c
日期:2001.11.1
neopentyl ligands, consistent with the formation of σ-neopentane complexes prior to neopentane elimination. The thermolysis of 1 in a 1:1 molar mixture of tetramethylsilane-h12 and tetramethylsilane-d12 (70 °C, 40 h) yields an intermolecular KIE of 1.07(4):1. Thermolysis of 1 and 2 in 1:1 benzene/benzene-d6 yields intermolecular KIEs of 1.03(5):1 and 1.17(19):1, respectively. The KIE values are inconsistent
Cp * W(NO)(CH 2 CMe 3)2(1)和Cp * W(NO)(CH 2 CMe 3)(CH 2 C 6 H 5)(2)在中等条件下(70°C,40 h )分别生成反应性络合物Cp * W(NO)(CHCMe 3)(A)和Cp * W(NO)(CHC 6 H 5)(B),它们通过在整个反应室中添加C-H来活化烃类溶剂M C键。α氘代导数Cp * W(NO)(CD 2 CMe 3)2(1-d 4)在新戊基配体内进行分子内H / D交换,这与消除新戊烷之前σ-新戊烷配合物的形成一致。在四甲基硅烷-h 12和四甲基硅烷-d 12的1:1摩尔混合物中热解1(70°C,40 h),得到的分子间KIE为1.07(4):1。热解1和2在1:1个的苯/苯d 6分别为1,:1.03产率间KIES(5):1和1.17(19)。KIE值与确定M的CH键的速率确定不一致C键,表明底物与金属中心的配位是烷烃和芳烃分子间竞争的决定性因素。Cp
Thermal Alkane C−H Bond Activation by a Tungsten Alkylidene Complex: The Reversal of α-Hydrogen Elimination
作者:Elizabeth Tran、Peter Legzdins
DOI:10.1021/ja9704850
日期:1997.5.1
Mechanism of activation of carbon-hydrogen bonds in tetramethylsilane and mesitylene and mechanism of intramolecular activation in trimethylphosphine on thermolysis of tetrakis(trimethylphosphine)hydridoneopentylosmium(II)
作者:Ronald S. Shinomoto、Peter J. Desrosiers、T. Gregory P. Harper、Thomas C. Flood
DOI:10.1021/ja00158a032
日期:1990.1
Thermal Activation of Hydrocarbon C−H Bonds by Tungsten Alkylidene Complexes
作者:Craig S. Adams、Peter Legzdins、Elizabeth Tran
DOI:10.1021/ja002457e
日期:2001.1.1
quantitative yields. The neopentylidene intermediate A can be trapped by PMe(3) to obtain CpW(NO)(=CHCMe(3))(PMe(3)) in two isomeric forms (4a-b), and in benzene, 1 cleanly forms the phenylcomplex CpW(NO)(CH(2)CMe(3))(C(6)H(5)) (5). Kinetic and mechanistic studies indicate that the C-H activation chemistry derived from 1 proceeds through two distinct steps, namely, (1) rate-determining intramolecular alpha-H
Perdeuteration of Arenes via Hydrogen Isotope Exchange Catalyzed by the Superbasic Sodium Amide Donor Species NaTMP·PMDETA
作者:Andreu Tortajada、Eva Hevia
DOI:10.1021/jacs.2c09778
日期:2022.11.9
Here we report the use of a simple sodium amide, NaTMP (TMP = 2,2,6,6-tetramethylpiperidide), combined with tridentate Lewis donor PMDETA (N,N,N′,N″,N″-pentamethyldiethylenetriamine), which is able to catalytically promote the HIE of a series nonactivated arenes under mild reaction conditions using C6D6 as the deuteriumsource. Establishing the potential of NaTMP for the deuteration of aromatic molecules
氢同位素交换 (HIE) 已成为制备氘代分子的研究最多的方法之一,最近主要关注过渡金属的金属催化 C-H 活化。在这里,我们报告了使用简单的氨基钠 NaTMP(TMP = 2,2,6,6-四甲基哌啶)与三齿 Lewis 供体 PMDETA(N,N,N ',N '' ,N '' -五甲基二亚乙基三胺)结合使用能够在温和的反应条件下使用 C 6 D 6催化促进一系列非活化芳烃的 HIE作为氘源。建立 NaTMP 用于芳香分子氘化的潜力,几种非活化底物,如萘、二苯乙炔和二苯乙烯可以在温和的反应条件下被氘化,而不需要过渡金属。将 NMR 研究与关键有机金属中间体的分离相结合,我们证明 NaTMP/PMEDTA 部分金属化 C 6 D 6的能力,同时产生 TMP(D),是实现催化氘化的关键。