Tertiary Amine-Catalyzed Acyl Group Exchange Reaction of<i>N</i>,<i>O</i>-Diacyl-<i>o</i>-aminophenols. Its Mechanism and Factors Determining the Relative Stability of Acyl Exchanged Isomer Pairs
作者:Tadamitsu Sakurai、Shuichi Kojima、Hiroyasu Inoue
DOI:10.1246/bcsj.63.3141
日期:1990.11
polarities. It was found that the relative stability of acyl exchanged isomer pairs is determined solely by the inductive effect of acyl groups, provided that the steric hindrance of acyl substituents bonded to amide nitrogen affects the stability to the same extent. The importance of steric hindrance exerted by a bulky acyl group in determining the relative stability was demonstrated by analyzing the
已经在不同极性的溶剂中研究了酰基取代基对各种 N,O-二酰基-o-氨基苯酚的酰基交换反应的平衡和速率常数的影响。发现酰基交换的异构体对的相对稳定性仅由酰基的诱导作用决定,条件是与酰胺氮键合的酰基取代基的空间位阻对稳定性产生相同程度的影响。通过分析标准自由能变化 (ΔG°) 和 pKa 之间的相关性,证明了由庞大的酰基施加的空间位阻在确定相对稳定性方面的重要性,标准自由能变化 (ΔG°) 和 pKa 用作异构体对的相对稳定性的量度和分别为酰基的吸电子能力。另一方面,酰基迁移反应的催化速率常数的对数与 pKa 值密切相关。除了这个发现之外,激活熵的大负值 ΔS\eweq=...