作者:Cole L. Cruz、David A. Nicewicz
DOI:10.1021/acscatal.9b00465
日期:2019.5.3
governing factors in the cation radical Newman–Kwart rearrangement are described. Through a combination of spectroscopic and kinetic analyses, it has been shown that the reactive intermediate is a thione cation radical that has significant thiyl radical character. This intermediate undergoes similar chemistry, such as olefin stereomutation, that has been observed for thiyl radicals generated by other means
描述了阐明阳离子自由基纽曼-科沃特重排中的控制因素的工作。通过光谱分析和动力学分析的组合,已经表明反应性中间体是具有显着的噻吩基特征的硫酮阳离子基。该中间体经历类似的化学反应,例如烯烃立体变化,已经观察到通过其他方式产生的噻吩基。此外,动力学研究表明,在系统中观察到的电子依赖性是硫酮阳离子自由基的限速分子内亲核捕获的结果。重要的是,反应性中间体的巯基自由基特性可用于合理化所有反应观察结果。该机理模型与在较高稀释度下观察到的速率增加相符,这减少了循环外中间体的形成。设计了一个热化学循环来预测哪些底物最容易进行阳离子自由基介导的重排。