Carboxyl radical-assisted 1,5-aryl migration through Smiles rearrangement
作者:Asik Hossian、Ranjan Jana
DOI:10.1039/c6ob01758d
日期:——
We report herein, a silver(I)-catalyzed Smiles rearrangement of 2-aryloxy- or 2-(arylthio)benzoic acids to provide aryl-2-hydroxybenzoate or aryl-2-mercaptobenzoate dimer, respectively, through 1,5-aryl migration from oxygen or sulfur to carboxylate oxygen. Mechanistically, the aryl ether moiety undergoes an intramolecular ipso attack by the carboxyl radical followed by a C–O or C–S bond cleavage.
A photoredox-neutral Smiles rearrangement of 2-aryloxybenzoic acids
作者:Jose. C. Gonzalez-Gomez、Nieves P. Ramirez、Teresa Lana-Villarreal、Pedro Bonete
DOI:10.1039/c7ob02579c
日期:——
We report on the use of visible light photoredox catalysis for the radical Smilesrearrangement of 2-aryloxybenzoic acids to obtain aryl salicylates. The method is free of noble metals and operationally simple and the reaction can be run under mild batch or flow conditions. Being a redox neutral process, no stoichiometric oxidants or reductants are needed.
Formation of dibenzofurans by flash vacuum pyrolysis of aryl 2-(allyloxy)benzoates and related reactions
作者:Michael Black、J. I. G. Cadogan、Hamish McNab
DOI:10.1039/c002480e
日期:——
Flashvacuumpyrolysis (FVP) of aryl 2-(allyloxy)benzoates 5 and of the corresponding aryl 2-(allylthio)benzoates 6 at 650 °C, gives dibenzofurans 19 and dibenzothiophenes 20, respectively. The mechanism involves generation of phenoxyl (or thiophenoxyl) radicals by homolysis of the O-allyl (or S-allyl) bond, followed by ipso attack at the ester group, loss of CO2 and cyclisation of the resulting aryl
Synthesis of salicylates from anionically activated aromatic trifluoromethyl group
作者:Huilin Xie、Chuankai Lin、Ruixiang Wang、Jin-Biao Liu
DOI:10.1016/j.tetlet.2021.153592
日期:2022.1
An efficient approach to salicylates via a novel transformation of anionically activated aromatic trifluoromethylgroup is described. Anionically activated trifluoromethylgroup can react with phenols/alcohols under alkaline conditions to afford aryl/alkyl salicylates in high yields. Mechanism studies indicate that the carbonyl oxygen atom of ester is from the H2O in the solvent.
We report herein a cerium photocatalyzed aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement. This operationally simple protocol utilizes inexpensive CeCl3 as a photocatalyst and converted a variety of 2-aryloxybenzoic acids into aryl-2-hydroxybenzoates in good yields.