Abstract: A process for preparing an enantiomerically enriched cycloalkene-substituted alanine compound having the structure: by asymmetrically hydrogenating a dehydro amino acid compound having the structure: in a suitable reaction media in the presence of a catalyst having a transition metal moiety complexed to a chiral phosphine ligand to prepare enantiomerically enriched cycloalkene substituted alanine compounds having the structure of Formula (IA) or (IB), which are key intermediates for the ACE inhibitors ramipril and perindolpril:

Abstract: A process for producing an enantiomerically enriched compound of Formula I: where the R-configuration, or S-configuration at the stereogenic center is marked with an *; by hydrogenating an enamide of formula III: in an organic solvent in the presence of a catalyst comprising a transition metal selected from rhodium or iridium, complexed to a chiral diphosphine ligand; Ar is optionally substituted phenyl; Z is OR1, SR1 or NR1R2; and P is R3, OR3 or NR3R4; R1 and R2 are selected from H, C1-8 alkyl, C5-12 cycloalkyl, aryl and aryl-C1-2-alkyl; or R1 and R2 together with the nitrogen atom form a C4-7-membered heterocyclic ring optionally fused with a 5- to 6-membered carbocyclic or heterocyclic ring; and R3 and R4 are selected from H, C1-8 alkyl, aryl, C5-12 cycloalkyl and aryl-C1-2-alkyl; or R3 and R4 together with the nitrogen atom form a C4-7-membered heterocyclic ring.

Abstract: A process for preparing an enantiomerically enriched cycloalkene-substituted alanine compound having the structure: by asymmetrically hydrogenating a dehydro amino acid compound having the structure: in a suitable reaction media in the presence of a catalyst having a transition metal moiety complexed to a chiral phosphine ligand to prepare enantiomerically enriched cycloalkene substituted alanine compounds having the structure of Formula (IA) or (IB), which are key intermediates for the ACE inhibitors ramipril and perindolpril: