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
Ytterbium(III) Triflate Catalyzed Tandem Friedel−Crafts Alkylation/Hydroarylation of Propargylic Alcohols with Phenols as an Expedient Route to Indenols
作者:Xiaoxiang Zhang、Wan Teng Teo、Philip Wai Hong Chan
DOI:10.1021/ol901981s
日期:2009.11.5
A method to prepare indenols efficiently by ytterbium(III) triflate catalyzed tandem Friedel−Crafts alkylation/hydroarylation of propargylic alcohols with phenols is described. The reaction was accomplished in moderate to excellent yields and regioselectivity under mild conditions and offers a straightforward and convenient one step synthetic route to bioactive indenols and its derivatives.