Catalytic Enantioselective Aldol Reactions of Pyruvates as Nucleophiles with Chlorinated and Fluorinated Aldehydes and Ketones.

Reactions of pyruvates as nucleophiles under catalytic conditions are difficult to control without the use of enzymes as catalysts. Here, enantioselective aldol reactions of pyruvates with chlorinated and fluorinated aldehydes and ketones under organocatalytic conditions, in which pyruvates act as nucleophiles, are reported. Based on analyses of self-aldol reactions of pyruvates in the presence of model catalysts, catalysts of the desired cross aldol reactions were developed. Using the primary amine-derived catalyst, the desired aldol products, i.e., γ-chlorinated alkyl or γ-fluorinated alkyl group-substituted γ-hydroxy α-ketoesters, were obtained in good to high yields with high enantioselectivities.