Heterogeneous Organic Base-Catalyzed Reactions Enhanced by Acid Supports

Amorphous silica-alumina-supported amines (SA-NR2) were found to be excellent heterogeneous catalysts for a variety of carbon−carbon bond-forming reactions, such as cyano-O-ethoxycarbonylation, Michael reaction, and nitro-aldol reaction. These reactions were hard to proceed either with amines alone or on the SA alone. Solid-state 13C MAS NMR analysis revealed the acid−base interaction of the H+ site and amine group on the SA-NR2 surface, which makes an acid−base dual activation mechanism possible for carbon−carbon bond-forming reactions.