A switchable redox annulation of 2-nitroarylethanols affording <i>N</i>-heterocycles: photoexcited nitro as a multifunctional handle
作者:Bin Wang、Hongyuan Ren、Hou-Ji Cao、Changsheng Lu、Hong Yan
DOI:10.1039/d2sc03590a
日期:——
The efficient transformation of nitroaromatics to functional molecules such as N-heterocycles has been an attractive and significant topic in synthesis chemistry. Herein, a photoexcited nitro-induced strategy for switchable annulations of 2-nitroarylethanols was developed to construct N-heterocycles including indoles, N-hydroxyl oxindoles and N–H oxindoles. The metal- and photocatalyst-free reaction
将硝基芳烃有效转化为功能性分子(如N-杂环)一直是合成化学中一个有吸引力且重要的课题。在此,开发了一种光激发硝基诱导的 2-硝基芳基乙醇可切换环化策略,以构建包括吲哚、N-羟基羟吲哚和N - H 羟吲哚在内的N-杂环。不含金属和光催化剂的反应通过支链羟基烷基和硝基单元的分子内氧化还原 C-N 偶联进行,该反应由双氢原子夺取 ( d -HAA) 过程引发。可转换反应结果的关键是二硼试剂通过其有利的氧转移反应性到原位介导生成亚硝基物种。该协议的实用性通过广泛的底物范围、优异的产量、官能团耐受性和广泛的应用得到了很好的证明。最后,进行了详细的机理研究,动力学同位素效应 (KIE) 实验表明 C-H 键的均裂参与了速率决定步骤。