Asymmetric Aldol Reaction Induced by Chiral Auxiliary

An asymmetric aldol reaction based on the use of (4R,5S)-1,5-dimethyl-4-phenylimidazolidin-2-one as a chiral auxiliary is described involving a three-step procedure: preparation of the chiral auxiliary from readily available (–)-ephedrine and urea in a solventless fashion, coupling of the chiral auxiliary to the ester functional group, and aldol condensation via in situ formation of the corresponding boron enolate.