作者:Christopher B. DeZutter、John H. Horner、Martin Newcomb
DOI:10.1039/c0ob00588f
日期:——
The 1-hydroxy-1-methyl-6,6-diphenyl-5-hexenyl radical (4a) and the 1-hydroxy-1-methyl-7,7-diphenyl-6-heptenyl radical (4b) were prepared from the corresponding PTOC esters (anhydrides of a carboxylic acid and N-hydroxypyridine-2-thione). The key step in the synthetic method for the precursors was a coupling reaction of the respective carboxylic acids with the thiohydroxamic acid, which was conducted
用相应的方法制备1-羟基-1-甲基-6,6-二苯基-5-己烯基(4a)和1-羟基-1-甲基-7,7-二苯基-6-庚烯基(4b) PTOC酯(羧酸和N-羟基吡啶-2-硫酮)。用于前体的合成方法中的关键步骤是各个羧酸与硫代异羟肟酸的偶联反应,反应进行了约10分钟。5分钟,然后快速色谱纯化。速率常数的基团环化图4a和图4b中乙腈通过激光闪光光解法直接在–30至60°C之间测量了四氢呋喃和四氢呋喃中的四价铬。阿雷尼乌斯(Arrhenius)在乙腈对于4a和4b,分别为log k = 9.9–2.6 / 2.303 RT和log k = 8.9–4.4 / 2.303 RT(kcal mol -1)。在室温下9×10 7 s -1和4×10 5 s -1的环化速率常数比类似烷基的环化速率常数大。室温下H原子俘获4a的粗速率常数苯硫酚和4b由叔丁基硫醇分别为k T= 1.2×10 9 M -1 s -1和k