A regioselective radical C–H trifluoromethylation of aromaticcompounds was developed using cyclodextrins (CDs) as additives. The C–H trifluoromethylation proceeded with high regioselectivity to afford the product in good yield, even on the gram scale. In the presence of CDs, some substrates underwent a single trifluoromethylation selectively, whereas mixtures of single- and double-trifluoromethylated
使用环糊精 (CD) 作为添加剂开发了芳香族化合物的区域选择性自由基 C-H 三氟甲基化。C-H三氟甲基化以高区域选择性进行,以良好的收率提供产品,即使是克级规模。在 CD 存在的情况下,一些底物选择性地进行单三氟甲基化,而在没有 CD 的情况下形成单三氟甲基化产物和双三氟甲基化产物的混合物。1 H NMR 实验表明区域选择性是通过在 CD 腔内包含基底来控制的。
Arene Cyanation via Cation-Radical Accelerated-Nucleophilic Aromatic Substitution
作者:Natalie Holmberg-Douglas、David A. Nicewicz
DOI:10.1021/acs.orglett.9b02678
日期:2019.9.6
Herein we describe a cation radical-accelerated-nucleophilic aromatic substitution (CRA-SNAr) of alkoxy arenes utilizing a highly oxidizing acridinium photoredox catalyst and acetone cyanohydrin, an inexpensive and commercially available cyanide source. This cyanation is selective for carbon-oxygen (C-O) bond functionalization and is applicable to a range of methoxyarenes and dimethoxyarenes. Furthermore
TCDA: Practical Synthesis and Application in the Trifluoromethylation of Arenes and Heteroarenes
作者:Jian Wang、Xiaomin Zhang、Zehong Wan、Feng Ren
DOI:10.1021/acs.oprd.6b00079
日期:2016.4.15
A practical synthesis of the reagent trimethylsilyl chlorodifluoroacetate (TCDA) is reported on 50 g scale. The trifluoromethylation with TCDA was optimized, and the reaction shows very broad scope with respect to electron-deficient, -neutral, -rich aryl/heteroaryl iodides, as well as excellent functional group tolerability, such as ester, amide, aldehyde, hydroxyl, and carboxylic acid. The reagent
A transition-metal-free direct oxidative trifluoromethylation of unsymmetrical biaryls has been achieved by the simple combination of trifluoromethanesulfinate and phenyliodine bis(trifluoroacetate). The trifluoromethylation is selectively observed in the electron-rich arenes.