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 C-13 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.