| abstract |
A novel oxotitanium complex represented by general formula (I) is disclosed: ##STR1## wherein R 1 and R 2 may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a phenyl group, a substituted phenyl group, a trialkylsilyl group, a monoalkyldiphenylsilyl group, a dialkylmonophenylsilyl group, a triphenylsilyl group, a substituted triphenylsilyl group, or a lower alkoxycarbonyl group, provided that R 1 and R 2 may be bonded to each other to form a hydrocarbon ring or a substituted hydrocarbon ring in cooperation with the carbon atoms to which R 1 and R 2 are bonded; R 3 and R 4 may be the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a benzoyl group, a benzenesulfonyl group, or a halogen atom, provided that R 3 and R 4 may be bonded to each other to form a hydrocarbon ring or a substituted hydrocarbon ring in cooperation with the carbon atoms to which R 3 and R 4 are bonded; and n is 1 or 2. The novel oxotitanium complex is useful as an asymmetric reaction catalyst. A process for producing a β-hydroxy ketone or an α-hydroxy carboxylic acid ester in the presence of the novel oxotitanium complex is also disclosed. |