Proline-β3-amino-ester dipeptides as efficient catalysts for enantioselective direct aldol reaction in aqueous medium

(Chemical Equation Presented) Dipeptides obtained from L-proline and β3-L-amino acids are reported to catalyze enantioselective direct aldol reaction in aqueous medium, leading to significant anti: syn diastereomeric ratios and enantiomeric excesses. The simple introduction of a polar substituent at the C-2 position of the β3-L-amino acid was also found to enhance appreciably both diastereo- and enantioselectivity of the catalyst. © 2009 American Chemical Society.