Electron‐Poor Acridones and Acridiniums as Super Photooxidants in Molecular Photoelectrochemistry by Unusual Mechanisms
摘要:
摘要据报道,缺电子的吖啶酮和原位生成的吖啶鎓盐是强效的闭壳光氧化剂,其作用机制令人惊讶。当用羰基(吖啶酮)桥接无环三芳基胺催化剂时,它们的行为完全从开壳、自由基阳离子、"超越扩散 "的光催化转变为闭壳、中性、扩散控制的光催化。吖啶酮的布氏酸活化可显著提高激发态氧化能力(+0.8 V)。质子化吖啶酮还原后,会转化为缺电子的吖啶鎓盐,成为更强的光氧化剂(*E1/2=+2.56-3.05 V vs SCE)。它们甚至能氧化缺电子的烯烃,而传统的吖啶鎓盐光氧化剂迄今为止仅限于氧化富电子的烯烃。令人惊讶的是,在光激发时,这些缺电子的吖啶鎓盐似乎会经历两个电子的还原淬火,形成吖啶阴离子,并通过光谱检测到其质子化形式。这种新行为在一定程度上得益于催化剂与炔的预组装,并与吖啶鎓盐的传统 SET 还原淬火形成鲜明对比。重要的是,这项研究说明了最初被认为是光催化剂的氧化还原活性发色分子是如何在反应过程中转变为具有完全不同的氧化还原和光谱特性的催化活性物种的。
Copper‐catalyzed synthesis of
<i>N</i>
‐aryl acridones from 2‐amino benzophenones and aryl boronic acids via sequential double oxidative C–N coupling
作者:Yang He、Liang Xu、Jinli Zhang、Yu Wei
DOI:10.1002/aoc.5316
日期:2020.2
Pot‐economic synthesis of N‐aryl acridones was performed with 2‐aminobenzophenones and aryl boronic acids as starting materials. Cu‐catalyzed chelation‐assisted oxidative C–N cross‐coupling reactions were well merged with the following intra‐molecular oxidative dehydrogenative C–H amination reactions under an air atmosphere. The use of reagent capsules can further resolve the compatibility problem
Copper-catalyzed intramolecular direct amination of sp2 C–H bonds for the synthesis of N-aryl acridones
作者:Wang Zhou、Yong Liu、Youqing Yang、Guo-Jun Deng
DOI:10.1039/c2cc35425j
日期:——
A copper-catalyzed approach for the synthesis of N-arylacridones via sp(2) C-H bond amination using air as oxidant under neutral conditions is disclosed. This reaction not only provides a complementary method for synthesizing medicinally important acridones, but also offers a new strategy for sp(2) C-H bond amination.