The highly stereoselective ring opening of N-tosylaziridine 2-carboxylate esters with LiAlH4 followed by oxidation of the ensuing syn alcohols results in a highly efficient 4 step asymmetric synthesis of alpha-methyl beta-amino acids from N-sulfinylaziridine 2-carboxylate esters. (C) 1997 Elsevier Science Ltd.