Synthesis of Novel Heteroquaterphenoquinones and Their Electrochemical, Structural, and Spectroscopic Characterization
作者:Kazuko Takahashi、Atsushi Gunji、Kazunori Yanagi、Misao Miki
DOI:10.1021/jo9600363
日期:1996.1.1
cross-coupling reaction or by a more convenient one-pot oxidative homocoupling reaction of heterocycle-substituted phenols. Despite a highly conjugation-extended system, the quinones 3-6 are very stable in the solid state and in solution in common organic solvents. These quinones undergo a reversible one-stage, two-electron reduction up to dianions and a two-stage, one-electron oxidation reaction up to dications
新型杂四苯醌,5,5'-双(3,5-二叔丁基-4-氧代-2,5-环己二-1-亚基)-5,5'-二氢-2,2'-二苯基(3 )及其2,2'-双亚乙烯基(4),2,2'-联呋喃基(5)和2,2'-bi-N-甲基吡咯基(6)类似物是通过逐步交叉偶联反应或通过更方便的杂环取代的酚的一锅氧化均偶联反应。尽管具有高度共轭扩展的体系,但醌3-6在固态和在普通有机溶剂中的溶液中非常稳定。这些醌经历可逆的一步两电子还原直至阴离子,再经历一步两电子氧化反应直至阳离子。这些醌的E(1)(红色)随着引入的杂环的芳香性的增加而增加。这些醌的E(1)(ox)似乎是由所掺入杂环的电离势确定的。因此,在醌3-6中,表现出最低的E(1)(ox)值的N-甲基醌6表现出最小的E(1)(sum)。通过X射线晶体学发现醌5以不寻常的O-顺式构型存在于固态,而醌3以S-反式构型存在于固态。顺式和反式异构体在3-5中可相互转化,而在(1)H