Nickel-Catalyzed Formal Homocoupling of Methoxyarenes for the Synthesis of Symmetrical Biaryls via C–O Bond Cleavage
作者:Keisuke Nakamura、Mamoru Tobisu、Naoto Chatani
DOI:10.1021/acs.orglett.5b03151
日期:2015.12.18
A new method has been developed for the nickel-catalyzed homocoupling of methoxyarenes via C–O bond cleavage using a diboron reagent. The use of 1,3-dicyclohexylimidazol-2-ylidene as a ligand was found to be critical to the success of the reaction. This new method allows the synthesis of a wide range of biaryl compounds.
pyrene and perylene derivatives were explored. The radical cation of 1,3,6,8-tetraarylpyrene 1 was examined by ESR, UV–vis–NIR spectroscopy and theoretical calculations. The addition of 2 equiv of oxidant to 1 resulted in the formation of dication 12+. The single-crystal X-ray structure of 12+ proved that the aromatic part relocates from biphenyl unit to naphthyl unit upon 2e− oxidation of 1. We have also
Generation of arenium ions by a self-protonation reaction in an aprotic molten salt medium
作者:A. C. Buchanan、A. S. Dworkin、G. P. Smith
DOI:10.1021/ja00536a024
日期:1980.7
arene combined with arene oxidation by SbCl/sub3/. Naphthalene and phenanthrene, however, do not undergo this reaction. Evidence is presented which indicates that the self-protonation reaction proceeds through the oxidation of the arene to its radical cation by SbCl/sub3/, and that the function of AlCl/sub3/ is to enhance the oxidizing power of the Sb/sup 3 +//Sb/sup 0/ couple.
One-pot synthesis of dimerized arenes and heteroarenes under mild conditions using Co(<scp>i</scp>) as an active catalyst
作者:Adwitiya Pal、Arunabha Thakur
DOI:10.1039/d2ob01738e
日期:——
was achieved by employing 2 mol% of Co(II)catalyst 1 along with Zn dust at room temperature in 2–4 h. The Co(II)/Zn(0) system in situ generates Co(I) as an active catalyst. This catalyst can effectively substitute expensive Pd catalysts and hygroscopic and air-sensitive ZnCl2, generally employed to generate such dimerized heterocyclic cores. Pd is replaced with the Co core and anhydrous ZnCl2 is replaced
通过在室温下使用 2 mol% 的 Co( II ) 催化剂1和锌粉,在 2-4 小时内实现了二聚芳烃和杂芳烃系统的可行一锅法合成。Co( II )/Zn(0) 系统原位生成 Co( I ) 作为活性催化剂。这种催化剂可以有效地替代昂贵的 Pd 催化剂和吸湿性和空气敏感的 ZnCl 2,通常用于生成这种二聚杂环核。Pd 被 Co 核和无水 ZnCl 2取代被易于处理且高度经济的活化形式的锌粉所取代。虽然传统方法使用高温和/或更长的反应时间,但我们的合成策略实现了预期的目标,在室温下以适度的反应时间(2-4 小时)取代昂贵的试剂,产品产率高(70-89%)同时。Co( II ) 催化剂1易于合成、经济可行、热稳定且对空气或水分不敏感。该催化剂已通过 EPR、IR、CV 和紫外-可见光谱以及 EDX 研究得到很好的表征。
Solid-state nickel(0)-mediated Yamamoto coupling enabled by mechanochemistry
作者:Koji Kubota、Naoki Shizukuishi、Shotaro Kubo、Hajime Ito
DOI:10.1093/chemle/upae056
日期:2024.3.29
Herein, we report the first solid-state protocol for nickel(0)-mediated Yamamoto-coupling reactions using ball milling. A variety of aryl halides reacted efficiently in the presence of bis(cyclooctadiene)nickel(0) [Ni(cod)2] and 4,4'-di-tert-butyl-2,2'-bipyridyl under solid-state mechanochemical conditions, affording the corresponding biaryls in high yields. Considering that potentially harmful and