Versatile three-step procedures for syntheses of seven racemic gamma-f
luoro-alpha-amino acids are described. Alkylation of tert-butyl N-(dip
henylmethylene)glycinate with 1-bromo-2-fluoroalkanes gave N-protected
aminoacid esters both in anhydrous medium using lithium-diisopropylam
ide as base at low temperature or in a two phase system of 50% aqueous
sodium hydroxide and methylene chloride with triethylbenzylammonium c
hloride as the phase transfer catalyst at room temperature. Subsequent
two-step deprotection with citric acid and hydrochloric acid gave the
title compounds in 13-33% overall yields.