Khramov Dimitri M, Boydston Andrew J, Bielawski Christopher W
Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
Org Lett. 2006 Apr 27;8(9):1831-4. doi: 10.1021/ol060349c.
[reaction: see text] New synthetic methodology to a variety of 1,2,4,5-tetraaminobenzenes and their corresponding benzobis(imidazolium) salts has been accomplished. Palladium-catalyzed coupling of various 1,2,4,5-tetrabromo- or 1,2,4,5-tetrachlorobenzenes with aryl- or tert-alkylamines afforded the respective tetrakis(N-substituted)aminobenzenes in excellent yields. This enabled comparative solid-state structural analyses of this elusive class of electron-rich arenes with their oxidized derivatives. The tetraamines were found to undergo formylative cyclization to the corresponding benzobis(imidazolium) salts in good to excellent yields.
[反应：见正文] 已实现了多种1,2,4,5-四氨基苯及其相应的苯并双（咪唑鎓）盐的新合成方法。钯催化各种1,2,4,5-四溴苯或1,2,4,5-四氯苯与芳基胺或叔烷基胺的偶联反应，以优异的产率得到相应的四（N-取代）氨基苯。这使得能够对这类难以捉摸的富电子芳烃及其氧化衍生物进行比较固态结构分析。发现四胺能以良好至优异的产率进行甲酰化环化反应生成相应的苯并双（咪唑鎓）盐。
