Regioselectivity in Palladium-Catalyzed C−H Activation/Oxygenation Reactions
作者:Dipannita Kalyani、Melanie S. Sanford
DOI:10.1021/ol051486x
日期:2005.9.1
[reaction: see text] Palladium-catalyzeddirectedC-Hactivation/oxygenation reactions have been explored in a series of meta-substituted aryl pyridine and aryl amide derivatives. These transformations tolerate a diverse array of electron-donating and electron-withdrawing meta-substituents and generally proceed with high levels of regioselectivity for functionalization of the less sterically hindered
Bromination of phenols in bromoperoxidase-catalyzed oxidations
作者:Diana Wischang、Jens Hartung
DOI:10.1016/j.tet.2012.08.081
日期:2012.11
phenol changes from F via Cl, OCH3, C(CH3)3, and H to CH3. The polar effect in phenolbromination by the enzymatic method, according to a Hammett-correlation (ρ=−3), compares to reactivity of molecular bromine under identical conditions (ρ=−2). Hypobromous acid is not able to electrophilically substitute bromine for hydrogen at pH 6.2 in aqueous tert-butanol. The tribromide anion behaves in MES-buffered
Synthesis of Benzofuropyridines and Dibenzofurans by a Metalation/Negishi Cross-Coupling/S<sub>N</sub>Ar Reaction Sequence
作者:Guy J. Clarkson、Stefan Roesner
DOI:10.1021/acs.joc.2c02111
日期:2023.1.6
methodology for the synthesis of benzofuropyridines and dibenzofurans from fluoropyridines or fluoroarenes and 2-bromophenyl acetates is reported. This streamlined one-pot procedure consists of a four-step directed ortho-lithiation, zincation, Negishi cross-coupling, and intramolecular nucleophilic aromatic substitution, allowing for the facile assembly of a diverse set of fused benzofuro heterocycles.
Guaiacol transprotection: replacement of the phenoxy isopropyl protecting function by acetyl
作者:Craig M. Williams、Lewis N. Mander
DOI:10.1016/j.tetlet.2003.11.065
日期:2004.1
A one-step method for the conversion of isopropyl protected guaiacols to the corresponding acetates is reported. Treating 6-substituted isopropyl protected guaiacols with trimethylsilyl trifluoromethanesulfonate in a mixture of acetic anhydride and acetonitrile affords 6-substituted guaiacol acetates in yields ranging from 35% to 99%. (C) 2003 Elsevier Ltd. All rights reserved.