Cluster-Based Catalytic Hydrogenation with High Conversion and Reversible Enantioselectivity†

Four tetranuclear ruthenium carbonyl hydrido clusters consisting of the enantiomeric pairs
[H4Ru4(CO)10{μ-1,2-(R/S,R/S)-bdpp}] and [H4Ru4(CO)10{1,1-(R/S,R/S)-bdpp}] containing chiral
(R,R)- or (S,S)-bdpp [bdpp = (2R/S,4R/S)-2,4-bis(diphenylphosphino)pentane] have been
prepared and fully characterized. These clusters catalyze asymmetric hydrogenation of tiglic
acid [trans-2-methyl-2-butenoic acid] with high conversion rates (75−100%) under relatively
mild reaction conditions. Enantiomeric excesses of 40−46% were observed; the predominating
enantiomeric form of the hydrogenated product is dependent on the configuration of the
diphosphine ligand, indicating strong chiral induction.

四核钯羰基氢化物簇，由对映异构体对[H4Ru4(CO)10{μ-1,2-(R/S,R/S)-bdpp}]和[H4Ru4(CO)10{1,1-(R/S,R/S)-bdpp}]组成，其中包含手性(R,R)或(S,S)-bdpp[bdpp = (2R/S,4R/S)-2,4-双(二苯基膦基)戊烷]，已成功制备并进行了全面表征。这些簇催化的对映选择性氢化反应，在相对温和的反应条件下对丁二酸[反-2-甲基-2-丁烯酸]实现了高转化率（75−100%），观察到对映选择性为40−46%；氢化产物的优势对映体形式取决于双膦配体的构型，表明存在显著的立体诱导效应。