Cleavage of C(aryl)−CH
<sub>3</sub>
Bonds in the Absence of Directing Groups under Transition Metal Free Conditions
作者:Peng‐Fei Dai、Xiao‐Shan Ning、Hua Wang、Xian‐Chao Cui、Jie Liu、Jian‐Ping Qu、Yan‐Biao Kang
DOI:10.1002/anie.201901783
日期:2019.4.8
carbon–carbon σ‐bonds, especially for unreactive hydrocarbons, remain limited. Activation by ring strain, directing groups, or in the presence of a carbonyl or a cyano group is usually required. In this work, by using a sequential strategy site‐selective cleavage and borylation of C(aryl)−CH3 bonds has been developed under directing group free and transition metal free conditions. Methyl groups of various arenes
现在,有机化学家可以选择性地和顺序地构建碳-碳σ键,而选择性裂解碳-碳σ键的方法,特别是对于未反应的碳氢化合物,仍然受到限制。通常需要通过环应变,引导基团或在羰基或氰基的存在下进行活化。在这项工作中,通过使用顺序策略C(芳基)-CH 3的位点选择性裂解和硼化在指导无基团和无过渡金属的条件下开发了键。各种芳烃的甲基被选择性裂解并被硼基取代。机理分析表明,它是通过分子间的连续分子间氧化和由自由基脱羧反应生成的涉及芳基稳定的持久性硼基自由基的瞬态芳基自由基偶联而进行的。