Acetophenones o-substituted by halogen and methoxyl groups were hydrogenated in the presence of (NH2Et2){Ru2Cl5[(S)-tol-BINAP](2)} at 35 degrees C and 85 kg/cm(2) hydrogen pressure. The results showed that o-bromoacetophenone was a very active substrate and its asymmetric hydrogenation gave an o-bromo-alpha-phenylethanol with very high enantioselectivity (97% ee). o-Chloroacetophenone was moderately active and its hydrogenation product o-chloro-alpha-phenylethanol had a good enantioselectivity (82% ee). o-Fluoroacetophenone exhibited a low reactivity but its hydrogenation product o-fluoro-alpha-phenylethanol showed the highest enantioselectivity (99% ee) among all products. o-Methoxyacetophenone showed a low reactivity, and its hydrogenation product o-methoxyl-alpha-phenylethanol gave a low enantioselectivity (27% ee). The effects of various reaction conditions, such as hydrogen pressure, reaction temperature, solvents, reaction time, ligand concentration and addition of acid and base, were investigated.