Optimization of asymmetric hydrogenation of 3-phenyl-3-butenoic acid catalyzed by rhodium(I)-4,5-bis-2,2-dimethyldioxolane (DIOP)

Article abstract of DOI:10.1016/0022-328X(89)87295-X

Enantioselective, homogeneous hydrogenation of 3-phenyl-3-butenoic acid (1) has extensively been examined in the presence of the rhodium(I)/4,5-bis<(diphenylphosphino)methyl>-2,2-dimethyldioxolane (DIOP) catalyst systems.Optimization of the reaction conditions was undertaken mainly by controlling effects of added tertiary amines as well as solvent polarities on the enantio-selectivity of the product.The best asymmetric yield (85.1percent e.e.) was attained when the hydrogenation was carried out in the presence of triethylamine (5 molpercent) in 75percent aqueous methanol using a neutral rhodium-DIOP catalyst.