Enantioselective synthesis of β-amino acids based on BINAP—ruthenium(II) catalyzed hydrogenation

BINAP—Ru(II) catalyzed hydrogenation of β-substituted (E)-β-(acylamino)acrylic acids allows efficient enantioselective synthesis of β-amino acids. The Z double bond isomers which possess an intramolecular hydrogen bond between amide and ester groups are more reactive but are hydrogenated with poor enantioselectivity. BINAP—Rh(I) complexes afford only moderate stereoselectivity with the opposite sense of enantioselection.