Stereoselective synthesis of vic-halohydrins and an unusual Knoevenagel product from an organocatalyzed aldol reaction: A non-enamine mode

Stereoselective synthesis by an aldol reaction between chloroacetone and aldehyde was studied using a synthesized chiral organocatalyst and triethylamine. The reaction gave α-chloro-β-hydroxy ketones in excellent yield with high anti selectivity and enantioselectivity. The chiral organocatalyst was also used in the Knoevenagel reaction, which gave α-cyano-β-hydroxy ketones at a low temperature and the usual Knoevenagel product at a high temperature. Both products were obtained in good to moderate yield with good anti selectivity in the case of α-cyano-β-hydroxy ketone derivatives.

Graphical AbstractStereoselective synthesis of vic-halohydrins and an unusual Knoevenagel product were obtained using a newly synthesized chiral organocatalyst and triethylamine. The reaction gave the products in excellent yield with high anti selectivity and enantioselectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide