Asymmetric catalytic synthesis of lysine by hydrogenation of α-nitrocaprolactam

Abstract

The enantioselective hydrogenation ofα-nitrocaprolactam (I) is effected on a chiral Pd complex, obtainedin situ in the presence of S-α-phenylethylamine, to give S-α-aminocaprolactam (II), hydrolysis of which gives S-lysine. The optical yield varies from 1 to 13% according to the solvent and concentration of chiral ligand. On a Pd complex with S-N-isopropyl-α-phenylethylamine, enantioselective hydrogenation of (I) gives an excess of the S-enantiomer of (II) (2%). On a Pd complex with S-phenylalaninol, hydrogenation of (I) leads to the R configuration of (II) with EE 7.2%.