photocatalytic aerobicoxidative lactonization of arene C(sp2)–H bonds proceeds in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tert-butyl nitrite (TBN). Under the optimized conditions, a range of 2-arylbenzoic acids is converted into the corresponding benzocoumarin derivatives in moderate to excellent yields. This method is characterized by its atom economy, mild reaction conditions, the
Intramolecular Aromatic C–H Acyloxylation Enabled by Iron Photocatalysis
作者:Siqi Xia、Kunjun Hu、Chuanhu Lei、Jian Jin
DOI:10.1021/acs.orglett.0c00002
日期:2020.2.21
protocol for the intramolecular aromatic C-H oxygenation of 2-biphenylcarboxylic acids has been achieved via iron photocatalysis. The 2-biphenylcarboxylic acids with a diverse array of substituents at both phenyl rings could furnish the oxygenation products in good to excellent yields. We speculate that the aryl carboxylate-iron(III) complexes should generate the aroyloxy radicals and iron(II) upon visible
Organocatalytic Electrochemical C–H Lactonization of Aromatic Carboxylic Acids
作者:Sanzhong Luo、Longji Li、Qi Yang、Zongbin Jia
DOI:10.1055/s-0036-1591558
日期:2018.8
Radical Methods and their Strategic Applications in Synthesis Abstract An electrochemical strategy has been developed for radical arene carbon–oxygen bond formation. This reaction utilizes DDQ as a redox mediator, with inexpensive glassy carbon electrodes to facilitate an intramolecular lactonization of biphenyl-2-carboxylic acid derivatives via aromatic carboxyl radical substitution to give 6H-be
§这些作者同等贡献。 作为特别主题“现代自由基方法及其在合成中的战略应用”的一部分发布 抽象的 已经开发出一种用于自由基芳烃碳-氧键形成的电化学策略。该反应利用DDQ作为氧化还原介体,并具有廉价的玻璃碳电极,以通过芳族羧基自由基取代促进联苯-2-羧酸衍生物的分子内内酯化,得到6 H-苯并[ c ] chromen-6-one。 已经开发出一种用于自由基芳烃碳-氧键形成的电化学策略。该反应利用DDQ作为氧化还原介体,并具有廉价的玻璃碳电极,以通过芳族羧基自由基取代促进联苯-2-羧酸衍生物的分子内内酯化,得到6 H-苯并[ c ] chromen-6-one。
Copper catalyzed room temperature lactonization of aromatic C–H bond: a novel and efficient approach for the synthesis of dibenzopyranones
作者:Raju Singha、Shubhendu Dhara、Munmun Ghosh、Jayanta K. Ray
DOI:10.1039/c4ra13665a
日期:——
A novel and efficient methodology has been developed for the intramolecular aryl C–H oxidative lactonization of 2-arylbenzaldehyde using a low-cost CuCl catalyst and TBHP as the oxidant at room temperature.
acids furnishing substituted naphthoic acids occurs in good to excellent yields upon reaction with alkyl/vinyl/aryl organolithium and Grignardreagents, in the absence of a metal catalyst without the need to protect the carboxyl (CO2H) group. This novel nucleophilic aromatic substitution is presumed to proceed via a precoordination of the organometallic with the substrate, followed by an addition/elimination