Stereoselective Synthesis of Some γ‐ and δ‐Fluoro‐α‐amino Acids

( R )‐(−)‐2‐Amino‐4‐fluorobutyric acid ( 4c ) (32% ee) and six of its homologues 9 have been synthesized by diastereoselective alkylation (54–72% yield) of ( R )‐(+)‐camphor‐based glycine ester imines 1 with 1‐bromo‐2‐fluoro‐alkanes 6 , at low temperature, followed by deprotection. Similarly 1‐bromo‐3‐fluoropropane was used for the preparation of ( R )‐(−)‐5‐fluornorvaline ( 4d ) (42% ee). With 1‐bromo‐2‐fluoropropane ( 6a ) and its homologues (prepared by bromofluorination of 1‐alkenes) partial resolution occurs in the alkylation step, yielding mixtures of four diastereomers. Using ( R )‐1‐bromo‐2‐fluoro‐4‐methylpentane two diastereomeric alkylation products are formed (58% de). The overall yield of the three‐step procedure varied from 10% to 32%.