Synthesis of symmetric anhydrides using visible light-mediated photoredox catalysis
作者:Marlena D. Konieczynska、Chunhui Dai、Corey R. J. Stephenson
DOI:10.1039/c2ob25463h
日期:——
A new approach to anhydride formation is reported via activation of C–O bonds by the Vilsmeier–Haack reagent formed by Ru(bpy)3Cl2 and CBr4 in DMF. Various aryl and alkyl carboxylic acids are converted to the corresponding anhydrides in excellent yields.
Facile Synthesis of CarboxylicAnhydrides Using 4,5-Dichloro-2-[(4-nitrophenyl)sulfonyl]pyridazin-3(2<i>H</i>)-one
作者:Yong-Jin Yoon、Jeum-Jong Kim、Yong-Dae Park、Woo Song Lee、Su-Dong Cho
DOI:10.1055/s-2003-40512
日期:——
A novel and facile synthesis of carboxylic anhydrides from carboxylicacidusing 4,5-dichloro-2-[(4-nitrophenyl)sulfonyl[pyridazin-3(2H)-one (2) is presented. Treatment of aliphatic or aromaticcarboxylicacids with 2 in the presence of base in organic solvents gave the corresponding anhydrides in good or excellent yields.
high yields within 5–10 min. However, for nitro-substituted derivatives, unexpectedly, N,N-diethylamides were isolated without anhydride formation. These results indicated the pronounced effect of substituents in governing these potential side reactions which can significantly affect the yields of acylation reactions promoted by phosphonium species.
研究了由磷介导的羧酸活化作用形成酸酐。在各种体系下,取决于试剂的反应性,在碱的存在下苯甲酸的活化导致苯甲酸酐以不同的速率形成。使用Ph 3 P–I 2 / Et 3 N组合,大多数芳酸在5–10分钟内即可高产率转化为相应的酸酐。然而,对于硝基取代的衍生物,出乎意料的是,N,N分离了-二乙酰胺而没有酸酐形成。这些结果表明取代基在控制这些潜在的副反应中具有显着的作用,其可显着影响由phospho物种促进的酰化反应的产率。
Ligand-Free Palladium-Catalyzed Aerobic Oxidative Coupling of Carboxylic Anhydrides with Arylboronic Acids
作者:Weiyan Yin、Haifeng He、Yani Zhang、Tong Long
DOI:10.1002/asia.201402314
日期:2014.9
We report a new, effective and environmentally friendly protocol for selective aerobic oxidativecoupling of arylboronicacids with carboxylic anhydrides in the presence of ligand‐free palladium catalyst. The aryl benzoates are obtained in good to excellent yields.
A novel method for the mild photoredox‐mediated tandem radical acylarylation and tandem acylation/semipinacol rearrangement has been developed. The synthesis of highly functionalized ketones bearing all‐carbon α‐ or β‐quaternary centers has been achieved using easily available symmetric aromatic carboxylic anhydrides as the acyl radical source. The method allows for a straightforward introduction of