Patent ID: 6207853
Filing Date: 2001-03-27
Classification: C07C

Abstract:
A process for the preparation of an enantiomerically enriched 2-substituted succinic acid deriviative of formula 2, which comprises asymmetric hydrogenation of the dehydro precursor of formula 7 or 8, or a mixture thereof ##STR27##wherein R.sup.1 and R.sup.2 are independently selected from the group consisting of H, a salt-forming cation, and an organic group of up to 30 C atoms, and R.sup.3 and R.sup.4 are independently selected from H or an organic group of up to 30 C atoms, provided that R.sup.3 and R.sup.4 are not both H, wherein said asymmetric hydrogenation is carried out in the presence of a transition metal complex of a chiral phosphine ligand having the formula 10 ##STR28##wherein n is 0 to 6 and R represents at least one non-hydrogen organic group of up to 30 C atoms; wherein said transition metal is selected from the group consisting of rhodium, ruthenium, and iridium.