Enantioselective Hydrogenation of Ethyl 4-Chloro-3-oxobutyrate in Solutions of Organic Salts with Recycling of the Catalyst Ru-BINAP

Enantioselective hydrogenation of ethyl 4-chloro-3-oxobutyrate in ionic liquid systems containing tetraethylammonium bromide, 1-butyl-3-methylimidazolium hexafluorophosphate, or 1-butyl-3-methylimidazolium trifluoromethanesulfonate in the presence of the chiral catalyst Ru-BINAP ensures a high level of asymmetric induction after at least threefold recycling of the catalyst.