Beyond Acid Strength in Zeolites: Soft Framework Counteranions for Stabilization of Carbocations on Zeolites and Its Implication in Organic Synthesis
作者:Jose R. Cabrero-Antonino、Antonio Leyva-Pérez、Avelino Corma
DOI:10.1002/anie.201500864
日期:2015.5.4
The generation of a carbocation with an acid depends not only on the acidstrength but also on the ability of the counteranion to stabilize the positive charge left behind. Here we report that despite their relatively weak acidity, zeolites are able to generate and stabilize medium‐size (molecular weight ≈300 Da) delocalized carbocations on their surface under mild reaction conditions, as it can be
Propargylation of aromatic compounds using Ce(OTf)3 as catalyst
作者:Claudio C. Silveira、Samuel R. Mendes、Guilherme M. Martins
DOI:10.1016/j.tetlet.2012.01.046
日期:2012.3
Ce(OTf)(3) was successfully employed as catalyst for the activation of the hydroxyl group in the Friedel-Crafts reaction of aromatic compounds with propargylic alcohols in nitromethane. The products were obtained in good to excellent yields. (C) 2012 Elsevier Ltd. All rights reserved.
PMA-Silica Gel Catalyzed Propargylation of Aromatic Compounds with Arylpropargyl Alcohols under Solvent-Free Conditions
PMA-silica gel has been utilized to catalyze efficiently the propargylation of aromaticcompounds with arylpropargyl alcohols in the absence of solvent under environmentally benign conditions.