Asymmetric hydrogenation of tyrosine analogues in water.

Abstract

"The purpose of this study was to investigate the feasibility of using water for the synthesis of tyrosine analogues through asymmetric hydrogenation reactions. A variety of α-enamide substrates, varying in R groups and location on the benzene ring, were synthesized including methyl-2-(benzoylamino)-3-(p-butoxyphenyl)-propenoate, methyl-2-(benzoylamino)-3-(o-methoxyphenyl)-propenoate, and methyl-2-(benzoylamino)-3-(p-methoxyphenyl)-propenoate. These substrates were subsequently hydrogenated in water at 60 psi to produce methyl-2-(benzoylamino)-3-(p-methoxyphenyl)-propanoate, methyl-2-(benzoylamino)-3-(o-methoxyphenyl)-propanoate, and methyl-2-(benzoylamino)-3-(p-butoxyphenyl)-propanoate. These results confirmed that water can be used as the solvent for asymmetric hydrogenations of enamide ester materials to synthesize tyrosine analogues."