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
A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)–H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol
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。