Photoinduced Electron-Transfer Substitution Reactions via Unusual Charge-Transfer Intermediates
作者:John B. Miller、James R. Salvador
DOI:10.1021/jo015896k
日期:2002.1.1
impossible. Nonpolar reaction conditions were employed which made classical and nonclassical carbocation S(N)1 reaction pathways unlikely. The reaction rates were measured. Trapping experiments indicated that free radical reactions were uninvolved in the substitution product formation. A novel, photoinduced electron-transfer reaction mechanism involving a charge-transfer intermediate is proposed to explain
卤代烷烃(1-负载金刚烷,1-卤代降冰片烷,甲基氯)与同源系列的胺或醇(甲胺,2-甲基-2-氨基丙烷,甲醇或2-甲基-2-丙醇)的光诱导取代反应研究了相应的烷烃取代的胺或醚和HCl的形成。桥头碳的几何形状使得不可能进行S(N)2反应。采用非极性反应条件,这使得经典和非经典碳正离子S(N)1反应路径变得不可能。测量反应速率。诱捕实验表明自由基反应不参与取代产物的形成。提出了一种新的,涉及电荷转移中间体的光诱导电子转移反应机理,以解释观察到的仲胺和醚的产生。测量了激发波长依赖性(作用光谱),发现其与电荷转移配合物的紫外吸收光谱相当。研究了反应机理的立体化学意义。(1R,2S,5R)-薄荷醇的甲基醚的形成是在(1R,2S,5R)-薄荷基氯和甲醇之间的光反应中观察到的唯一有机反应产物。