Optically active N-sulfinimines underwent stereoselective Michael/nucleophilic addition domino reaction triggered by magnesium thiolate to give alpha-phenylthiomethyl-beta-(N-sulfinylamino) esters in high diastereomeric excess. The adducts were readily converted into optically active alpha-methylene-beta-(N-sulfinylamino)esters so that this reaction provides a useful asymmetric aza-Baylis-Hillman-equivalent method.