Synthesis, Characterization and Catalytic Behavior of some L-Hydroxyprolines Dimers for Asymmetric Aldol Reaction

Diesters derived from 4-L-hydroxyproline and malonic, succinic, glutaric or adipic acid are prepared and employed as enantioselective catalysts in the aldol reaction of pnitrobenzaldehyde with acetone. The catalytic properties are tested using different concentrations of the catalysts. A conversion of 50-100% and enantiomeric excess (ee) values of 74-84% are obtained with 20 % mol of the catalyst.