Organic Transformations over Silica Materials Modified by Covalently Bonded Surface Functional Groups.
Arpad Molnar and Bulcsu Rac
Affiliation: Department of Organic Chemistry, University of Szeged, Dom ter 8, H-6720 Szeged, Hungary.
The methods to prepare mesoporous silica materials and their derivatization by catalytically active functional groups covalently anchored to the surface are summarized. A short description of the major characterization techniques is also given. The transformations induced by solids with anchored basic functions mainly with various amino groups including oxidations, C-C forming reactions, and enantioselective alkylations are treated in details. A similar comprehensive analysis is given for processes catalyzed by anchored sulfonic acid groups. The important reactions studied are esterification, various condensations, protection of functional groups, and Friedel – Crafts reactions. The results of comparative studies are treated separately. The two final subsections are devoted to the application of bridged polysilsesquioxanes, also called periodic mesoporous organosilanes (PMOs) and cooperative acid – base catalysis.
Keywords: cyanosilylation, PMO sulfonic acid catalysts, MCM41, polysilsesquioxanes, Friedel, –, Crafts alkylation
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