A highly enantio- and diastereoselective direct aldol reaction in aqueous medium catalyzed by thiazolidine-based compounds

Taking l-aminoacids as starting materials, a new set of enantiopure thiazolidine-based organocatalysts were prepared using a simple synthetic approach and successfully applied in the asymmetric direct aldol reaction between various cyclic ketones and aldehydes in a saturated aqueous medium. The aldol adducts were obtained with excellent enantioselectivity (up to >99% ee) and diastereoselectivity (dr >20:1).