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.
Efficient Aryl Migration from an Aryl Ether to a Carboxylic Acid Group To Form an Ester by Visible-Light Photoredox Catalysis
作者:Shao-Feng Wang、Xiao-Ping Cao、Yang Li
DOI:10.1002/anie.201706597
日期:2017.10.23
We have developed a highly efficient aryl migration from an arylether to a carboxylic acid group through retro‐Smiles rearrangement by visible‐light photoredox catalysis at ambient temperature. Transition metals and a stoichiometric oxidant and base are avoided in the transformation. Inspired by the high efficiency of this transformation and the fundamental importance of C−O bond cleavage, we developed
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.
Herein, we report a catalytic radical-Smiles rearrangement system of arene migration from ether to carboxylic acid with riboflavin tetraacetate (RFT), a readily available ester of natural vitamin B2, as the photocatalyst and water as a green solvent, being free of external oxidant, base, metal, inert gas protection, and lengthy reaction time. Not only the known substituted 2-phenyloxybenzoic acids