Synthesis, structure, and thermal destruction of aroxytetraphenylstiboranes
摘要:
A series of aroxytetraphenylstiboranes, Ph(4)SbOAr, were obtained by the reaction of pentaphenylstiborane with phenols at similar to 20 degrees C. The thermolysis of these compounds gives O- or o-C-phenylation products. The thermolysis of stiboranes, which incorporate aryl groups containing electron-withdrawing substituents (Ar = 2,4-Br-2, 2,4-Cl-2, 2-NO2, 4-OPh) produces predominantly simple diaryl ethers of asymmetric structure in 58%, 90%, 32%, and 60% yields, respectively.
Formation of C(sp2)–X bonds was carried out using a Fe3O4@SiO2‐copper(I) sucrose xanthate nanoparticle catalyst with the aid of the copper(I) xanthate moiety in the catalyst which was prepared from the reaction between sucrose and carbon disulfide through an alkaline medium via the traditional Zeise approach. Various techniques were employed for the characterization of these novel nanoparticles. Three
C(sp 2)–X键的形成是利用Fe 3 O 4 @SiO 2-铜(I)蔗糖黄原酸酯纳米颗粒催化剂,借助由该催化剂制备的催化剂中的黄原酸铜(I)部分进行的。传统的Zeise方法通过碱性介质使蔗糖和二硫化碳之间发生反应。各种技术被用于表征这些新颖的纳米颗粒。三种杂原子N,O和S成功地进行了杂原子芳基化反应,分别生成仲胺或叔胺,醚和硫醚。
Ullmann diaryl ether synthesis catalyzed by copper (I)/pyridine-functionalized silane
作者:Baohua Zhang、Lanxiang Shi、Ruixia Guo、Sijie Liu
DOI:10.1080/10426507.2015.1119135
日期:2016.6.2
GRAPHICAL ABSTRACT ABSTRACT Ullmann-type diarylethersynthesis was performed under mild conditions in DMF/K2CO3 using a pyridine-functionalized silane as a ligand. The products were obtained in good yields. This method tolerates a variety of functional groups and is effective in the synthesis of hindered diarylethers and heteroaryl ethers.
be efficiently performed by means of catalytic amounts of copper iodide and the inexpensive ligand 1 (structure given in Table 1). The reaction is applicable to a wide range of substrates and proceeds at 60–80 °C, the lowest temperatures reported to date for an Ullmann-type synthesis of diarylethers. Moreover, the use of aryl bromides and inexpensive K3PO4 as base make this method attractive for applications
苯酚和芳基溴化物的偶联可通过催化量的碘化铜和廉价的配体1(表1中给出的结构)有效地进行。该反应适用于多种底物,反应温度为60–80°C,这是迄今为止报道的Ullmann型二芳基醚合成的最低温度。此外,使用芳基溴化物和廉价的K 3 PO 4作为碱使得该方法对于工业规模的应用具有吸引力。
A General and Mild Ullmann-Type Synthesis of Diaryl Ethers
作者:Henri-Jean Cristau、Pascal P. Cellier、Samy Hamada、Jean-Francis Spindler、Marc Taillefer
DOI:10.1021/ol036290g
日期:2004.3.1
[reaction: see text] An efficient method for the synthesis of diaryl ethers under particularly mild conditions is described. Inexpensive ligands were found to greatly accelerate the Ullmann-type coupling of aryl bromides or iodides with phenols. A series of diaryl ethers were obtained with excellent yields in acetonitrile in the presence of Cs(2)CO(3) and catalytic copper(I) oxide. The reaction tolerates
importance of ligand/copper-catalyzedarylations of nucleophiles in organic chemistry, the structural and electronic features that make a ligand efficient in these reactions have not been determined until now. In this work, several bidentate ligands involving pyridine and/or imine nitrogen binding sites such as our lead ligand 1 have been synthesized, and tested in phenol arylations with a view to