Synergistic Catalysis by Multifunctionalized Solid Surfaces for Nucleophilic Addition Reactions

This review paper treats with acid-base and Pd-complex-base bifunctional catalyst surfaces used to catalyze nucleophilic addition reactions. A silica–alumina-supported tertiary amine was found to be a highly active heterogeneous catalyst for Michael additions and cyano-ethoxycarbonylation. These reactions barely proceeded with either a homogeneous amine or silica–alumina support, indicating that synergistic catalysis occurred between the silica–alumina surface and basic amine. Silica–alumina, which contains both tertiary and primary amines, was an efficient catalyst for one-pot synthesis of 1,3-dinitroalkanes from aldehydes and nitromethane. The acid-base synergistic catalysis was applied to metal complex-base synergistic catalysis. Both the Pd-complex and tertiary amine-immobilized silica was an excellent heterogeneous catalyst for the Tsuji-Trost reaction. Spectroscopic analyses, such as solid-state MAS NMR, revealed the structures of prepared catalysts, immobilization mechanism of amine groups on the silica–alumina surface, and reaction intermediates and catalytic reaction mechanism. Substrate scope for the cyanation, Michael reaction, 1,3-dinitroalkane synthesis, and the Tsuji-Trost reaction are also described.