Enantioselective synthesis of alpha-fluorinated beta2-amino acids.

A methodology for the enantioselective synthesis of alpha-fluorinated beta2-amino acids has been developed from readily available carboxylic acids 3. Conversion to the Evan's oxazolidinone followed by enantioselective fluorination and alkylation gave 7 in high diastereomeric excess (>95%). Subsequent removal of the oxazolidinone and amination at the Bn-protected hydroxyl center gave optically active alpha-fluorinated beta2-amino acids.