Asymmetric transfer hydrogenation reaction in water: Comparison of chiral proline amide/amine ruthenium(II) complexes

•Chiral proline-derived chiral amide/diamine ligands 2 and 3 were prepared and used for ATH.•Chiral proline amide ligands having more acidic N–H gave better yields as compared with the corresponding amine derivatives.•The bulk of the aryl substituents on the ligand increased the enantioselectivity.

Chiral proline amide/amine ligands (2, 3), synthesized by multi-step reaction starting from l-proline (1), were evaluated as catalyst generated in situ from [RuCl2(p-cymene)]2 for asymmetric transfer hydrogenation of aromatic ketones in the presence of sodium formiate and sodium dodecyl sulfate (SDS). The results revealed that efficiencies and enantioselectivities strongly depend on the N-substituents.

Graphical abstractAsymmetric transfer hydrogenation of ketones using chiral proline amide/amine ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide