A Dendritic Active Site:  Catalysis of the Henry Reaction

Dendrimers containing an encapsulated tertiary amine were prepared by coupling tris(2-aminoethyl)amine with dendritic branches derived from l-lysine. These dendrimers were used as catalysts in the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde and nitroethane, and their catalytic performance was compared with that of triethylamine. Attachment of the dendritic shell alters the rate of reaction and influences the syn:anti ratio of products. It is proposed that the dendritic shell generates an encapsulated catalytically active site, mimicking the behavior of a protein superstructure.