Cobalt-Catalyzed Regioselective <i>para</i>-Amination of Azobenzenes via Nucleophilic Aromatic Substitution of Hydrogen
作者:Yigao Tao、Rong Hu、Zeyu Xie、Ping Lin、Weiping Su
DOI:10.1021/acs.joc.2c00026
日期:2022.4.1
The metal-catalyzed nucleophilic aromatic substitution of hydrogen (SNArH) via coordination of the substituent on the aromatic ring to the metal catalyst, in terms of reactivity, substrate type, and reaction selectivity, complements the transition metal-catalyzed C–H functionalization that proceeds via C–H metalation but remains an elusive target. Described herein is the development of an unprecedented
通过芳环上的取代基与金属催化剂的配位,金属催化的氢的亲核芳族取代 (S N ArH) 在反应性、底物类型和反应选择性方面,补充了过渡金属催化的 C-H 官能化通过 C-H 金属化进行,但仍然是一个难以捉摸的目标。本文描述了一种前所未有的钴催化偶氮苯对位选择性胺化的发展,其本质上是由 Hammett 分析揭示的金属促进的 S N ArH 过程,从而说明了芳烃环上的取代基与金属催化剂可能导致芳烃环向 S N亲电活化氩气。这种钴催化的方案允许使用多种脂肪胺和苯胺作为胺化试剂,耐受偶氮苯的电子多样化取代基,并以良好的产率提供相应的产品,并对对胺化具有区域特异性选择性。
Oxidative dimerization of anilines with heterogeneous sulfonic acid catalysts
suitably supported perfluorosulfonic acids can catalyze the oxidative dimerization of anilines using hydrogen peroxide as a clean oxidant. The reaction does not require the use of organic solvents and affords desired azobenzenes and water as products, minimizing the formation of wastes. The metal-free solid catalyst shows remarkable activity and selectivity for the reaction, which occurs under very mild
A Unique Alkylation of Azobenzenes with Allyl Acetates by Rh<sup>III</sup>-Catalyzed C–H Functionalization
作者:Hong Deng、Hongji Li、Lei Wang
DOI:10.1021/acs.orglett.5b00957
日期:2015.5.15
A novel RhIII-catalyzed direct alkylation of azobenzenes with allylacetates through C–H activation and functionalization is demonstrated in which the allylacetates serve as unique alkylation agents. The rhodium-catalyzed alkylation provides a highly efficient and atom-economic approach to a series of azo compounds.
Process for Producing 2,2'-Bis(Trifluoromethyl)-4,4'-Diaminobiphenyl
申请人:Namekata Takeshi
公开号:US20090069602A1
公开(公告)日:2009-03-12
A process for producing 2,2′-bis (trifluoromethyl)-4,4′-diaminobiphenyl which is useful as a raw material for polyimide resin, etc.
In benzidine rearrangement of 3,3′-bis(trifluoromethyl) hydrazobenzene in the presence of an inorganic acid such as sulfuric acid aqueous solution or concentrated hydrochloric acid, use of a water-immiscible organic solvent such as toluene as reaction solvent can increase the yield of the product.
3,3′-bis(trifluoromethyl) hydrazobenzene can be synthesized by reduction of m-nitrobenzotrifluoride.
hydrazoarenes using ethanol as a hydrogen source by a bidentate Ru(II)-NC complex is developed. A weak base is crucial for this semihydrogenation that can efficiently avoid hydrazoarene dehydrogenation under strongly basic conditions. Control experiments and density functional theory calculations demonstrate the mechanism via a Meerwein–Ponndorf–Verley mechanism, and the only byproduct is ethylacetate. This study