Highly stereoselective synthesis of anti-N-protected-alpha-amino epoxides

A simple and efficient method for the synthesis of anti-N-protected amino e poxides from carbamate-protected amino acids is described. The two key step s are the monobromination of a beta -ketoester and chelation-controlled red uction of a bromomethyl ketone intermediate. Good overall yields, high dias tereoselectivity, and excellent functional group compatibility are characte ristic.