Rate constants for 1,n-hydrogen transfer reactions in some amino acid derived radicals
作者:Le Zeng、Talbi Kaoudi、Carl H. Schiesser
DOI:10.1016/j.tetlet.2006.09.010
日期:2006.11
Absolute rate constants for 1,n-hydrogen atom transfers in some substituted amino acid derived radicals have been determined in benzene through the use of competitive kinetic experiments. Radicals derived from methyl N-(2-iodobenzoyl)-N-(tert-butyloxycarbonyl)glycinate, -alaninate, -leucinate, -tert-leucinate and -phenylglycinate undergo intramolecular 1,5-hydrogen atom transfer to afford the corresponding
通过使用竞争动力学实验,已经确定了苯中某些取代的氨基酸衍生基团中n氢原子转移的1的绝对速率常数。由N-(2-碘苯甲酰基)-N-(叔丁氧基羰基)甘氨酸甲酯,-丙氨酸酯,-亮氨酸酯,-叔亮氨酸酯和-苯基甘氨酸酯衍生的自由基经历分子内的1,5-氢原子转移以提供相应的α-氨基在80°C时速率常数在1.0-4.3×10 7 s -1范围内的酸酯基。如果氨基酸侧链中存在可抽象的氢原子,则1,6-和1,7-易位是竞争过程。