A series of new modular Ru/aminoalcohol systems were used as enantioselective catalysts in the asymmetric transfer hydrogenation reaction in both water and 2-propanol. The catalytic behavior exhibited in these two media follows different tendencies regarding the tunable ligand structure. While the bulkiness of the R1 group has a positive effect on the activity for reactions in 2-propanol, ligands with bulky R1 groups are generally less active ...