Unusual amino acids: II. Asymmetric Synthesis of Fluorine Containing Phenylalanines☆

Abstract Few (Z) -α-N-benzoylamino-β-(fluorophenyl)-acrylic acids and their esters were prepared by known procedures and hydrogenated to the corresponding optically active α-benzoyl-β-(fluorophenyl)-alanine derivatives with optical yields up to 90% using the rhodium complexes of “PROPRAPHOS” and O,N-bis(diphenylphosphino)-2-exo-hydroxy, 3-endo-methylamino-norbornane as chiral catalysts. The method proved to be apt for upscaling the preparation. Deacylation of the obtained amino acids gave the hydrochlorides of the fluorinated phenylalanines in very pure state.