ASYMMETRIC SYNTHESIS OF LYSINE DERIVATIVES BY DIASTEREOSELECTIVE HYDROGENATION
The hydrogenation of the S-α-phenylethylamide of 5-cyano-2-hydroxyiminovaleric acid at Raney nickel catalyst at atmospheric pressure in dioxane or tert-butyl alcohol with the addition of acetic anhydride leads to the formation of the corresponding amide of diacetyllysine having the preferred R configuration with a 10-14 percent excess of the R,S-diastereomer.Hydrogenation of the same substrate in solvents containing α-phenylethylamine takes place at increased pressure and gives the S-phenylethylamide of R-lysine with a 3-12percent excess of the diastereomer, depending on the employed solvent.