Both diastereomers of β-aminoester can be obtained diastereoselectively in the reaction of optically active N-sulfinimine possessing 2-methyl-1, 3-dioxolanyl group with ester enolate simply by changing the enolate metal species, additives, and solvents. The β-aminoester can be converted into the corresponding 3-unsubstituted β-lactam.
