Enantioselective Synthesis of Both Enantiomers of Phosphinothricin via Asymmetric Hydrogenation of α-Acylamido Acrylates

Article abstract of DOI:10.1021/jo00005a024

Both enantiomers of phoshinothricin (1), a naturally occuring amino acid that contains the unique methylphosphinate moiety, were prepared by asymmetric hydrogenation of α-acylamido acrylate precursors 7.L-1 and peptides containing L-1 are inhibitors of the enzyme glutamine synthetase (GS).Inhibition of GS is responsible for the antibiotical and herbicidal properties of these compounds.Synthesis of substrates 7 and parameters influencing the enantioselectivity are discussed.Substrate concentration and solvent polarity appear to have the most marked effects on enantiomeric excesses for a given catalyst system.Enantiomeric excesses reach 91percent for hydrogenations with (R,R)-NORPHOS- and (S,S)-CHIRAPHOS-derived catalysts.