A new family of phosphine ligands bearing a bulky carbazolyl scaffold is described. With the combination of ligand 2a and Pd(OAc)2, difficult tri-ortho-substituted biaryl couplings are accomplished smoothly. In particular, the catalyst loading as low as 0.02 mol% of Pd for non-activated 2,6-disubstituted aryl chloride coupling can be achieved.
Sulphuryl chloride as an electrophile. Part 5. Chlorination of some anthracene derivatives; molecular orbital modelling of substituent effects
作者:Roger Bolton、D. Brynn Hibbert、Simin Parand
DOI:10.1039/p29860000981
日期:——
The rates of electrophilic attack at C-10 of some 9-substituted anthracenes (9-H, Br, CHO, CN, NO2, OMe, or Bz) by sulphurylchloride have been measured (in PhCl 298 K). The substituent effects roughly parallel those expected from considering the simpler p-XC6H4 system (ρ–1.51; r 0.975); better agreement (ρ–1.23 ± 0.05; r 0.994) comes by using Dewar's FMMF treatment. MNDO calculations of the energy
已经测量了一些硫磺酰氯在C-10处对C的亲电进攻速率(9-H,Br,CHO,CN,NO 2,OMe或Bz)(在PhCl 298 K中)。取代基的影响大致与考虑使用更简单的p -XC 6 H 4体系(ρ-1.51;r 0.975)有关。通过使用杜瓦氏FMMF处理可获得更好的一致性(ρ–1.23±0.05; r 0.994)。MNDO对中间σ复合物的能量和最优化几何结构的MNDO计算显示出折叠结构,其允许一定程度的sp 3C-10原子的特征,同时在蒽离子中保持扩展的π系统足够的离域。遵循Bell-Eyring-Polyani原理,每种反应物与其σ络合物之间的计算能量差与Clδ +攻击过程中实验观察到的自由能变化之间存在线性关系。
Reactions of cupric halides with organic compounds—III
作者:D. Mosnaim、D.C. Nonhebel、J.A. Russell
DOI:10.1016/s0040-4020(01)82883-0
日期:1969.1
9-Alkyl and 9-arylanthracenes have been shown to undergo halogenation with cupric halides to give good yields of their 10-halogenated derivatives. Electron-donating groups in 9-arylanthracenes were shown to increase the rate of reaction. The results are interpreted in terms of a ligand-transfer mechanism.
Halogenations of Anthracenes and Dibenz[<i>a,c</i>]anthracene with <i>N</i>-Bromosuccinimide and <i>N</i>-Chlorosuccinimide<sup>1</sup>
作者:Shaoming Duan、Jeff Turk、Joseph Speigle、Jean Corbin、John Masnovi、Ronald J. Baker
DOI:10.1021/jo991495h
日期:2000.5.1
exclusively 9-(bromomethyl)anthracene with NBS in the absence of iodine, but mainly (67%) 9-bromo-10-methylanthracene in the presence of iodine. Chlorination of 3 with NCS in the presence of HCl also affords mostly (65%) nuclear halogenation. Nuclear bromination of anthracene, 9-methylanthracene, and dibenz[a, c]anthracene by NBS in the absence of added HBr is accelerated by iodine. This effect is
Anthracene is selectively chlorinated with solid copper(II) chloride to give a quantitative yield of 9-chloroanthracene. The tentative reaction mechanisms so far proposed fail to explain the nonreactivity of some other hydrocarbon homologues, e.g. naphthalene and phenanthrene, toward copper(II) chloride. The present study revealed that the oxidative half-wave potentials (E1⁄2ox) of all reactive hydrocarbon
蒽用固体氯化铜 (II) 选择性氯化,得到定量的 9-氯蒽。迄今为止提出的暂定反应机制未能解释一些其他烃同系物(例如萘和菲)对氯化铜 (II) 的非反应性。本研究表明,所有反应性烃类同系物的氧化半波电位 (E1⁄2ox) 均小于 1.26 V。基于这一发现,我们假设一个反应机制涉及从烃类到氯化铜 (II) 的一个电子转移.