Abstract (+)-(R)-and (−)-(S)-3, 3, 3-trifluoro-2-methyl-alanine (1) were synthesized from (+)- (R)-methyl-p-tolyl-sulphoxide (5) and N-alkoxycarbonylimino derivatives 4 of methyl 3, 3, 3- trifluoropyruvate (3). The absolute configuration was determined by X-ray analyses of two synthetic intermediates (2S, RS)-6a and (2R, R S-6c.