Asymmetric Aldol Reaction Catalyzed by Polymer-Supported Proline-Decorated Dendrons

Significance

The three types of non-peptidic ­hydroxyproline-based catalysts on dendronized supports Gn(Pro) (n = 1-3) were prepared from chloromethyl-terminated first-to-third generation of dendron resin Gn(Cl) (n = 1-3) with methyl ester of (2S,4R)-O-propargyl-N-trityl-4-hydroxyproline 1 (eq. 1). Asymmetric aldol reactions of acetone with benzaldehyde and 4-nitrobenzaldehyde were carried out in the presence of 0.3 equiv of catalyst Gn(Pro) (n = 1-3) in DMSO at room temperature for four days to give the aldol products in 35-95% yield and 67-85% ee (eq. 2).