Method for producing α- fluoro -β- amino acids

By reacting a ²-hydroxy-±-amino acid with sulfuryl fluoride (SO 2 F 2 ) in the presence of an organic base, it is possible to produce an ±-fluoro-²-amino acid of the formula [2]. By using a C8-12 tertiary amine having two or more alkyl groups of C3 or higher, and especially diisopropylethylamine, as the organic base, by-production of quantery ammonium salts is effectively suppressed. By applying the production process of the present invention, it is possible to very easily produce (2R)-3-(dibenzylamino)-2-fluoropropionic acid methyl ester, which is extremely important as a pharmaceutical intermediate, with high positional selectivity even on an industrial scale.