作者:James E. Johnson、Nora M. Morales、Andrea M. Gorczyca、Debra D. Dolliver、Michael A. McAllister
DOI:10.1021/jo010067k
日期:2001.11.1
The kinetics and mechanism of acid-catalyzed Z/E isomerization of O-methylbenzohydroximoyl chloride (1Za and 1Ea), methyl O-methylbenzohydroximate (1Zb and 1Eb), ethyl O-methylbenzohydroximate (1Zc and 1Ec and five para and meta substituted derivatives), O-methylcinnamohydroximoyl chloride (2Za and 2Ea), and methyl O-methylcinnamohydroximate (2Zb and 2Zb) have been investigated. The kinetics of Z/E
酸催化O-甲基苯并氢氧肟基氯(1Za和1Ea),O-甲基苯并氢肟酸甲酯(1Zb和1Eb),O-甲基苯并氢肟酸乙酯(1Zc和1Ec以及五种对位和间位取代的衍生物)的Z / E异构化动力学和机理,研究了O-甲基肉桂氢氧肟基氯(2Za和2Ea)和O-甲基肉桂氢氧肟酸甲酯(2Zb和2Zb)。这些亚胺的Z / E异构化动力学已在冰醋酸(1Ea和1Zc)和含HCl,三氟甲磺酸或四氟硼酸(1Ea,1Zb,2Ea和2Zb)的二恶烷溶液中进行了研究。异构化是通过(a)围绕质子化亚胺的碳-氮双键旋转(亚胺离子旋转)或(b)对质子化亚胺的亲核攻击形成四面体中间体而经历立体突变和亲核体损失(亲核催化)。羟肟基氯1Ea和2Ea仅通过亲核催化机理进行异构化。羟肟酸酯1Zb似乎能够通过任一机理异构化。羟肟酸酯2Zb可以仅通过亚胺离子旋转进行异构化。理论计算支持以下观念:质子化亚胺中的共轭增加会提高亚胺离子旋转的速率。氢