Process for preparing optically active alcoholic compounds

A process for preparing optically active alcoholic compounds by conducting asymmetric reduction of a prochiral carbonyl compounds represented by the general formula (1);

• wherein R1 and R2 are different from each other and represent a substituted or unsubstituted alkyl group containing 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group containing 7 to 30 carbon atoms, a substituted or unsubstituted aryl group containing 6 to 30 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group containing 1 to 20 carbon atoms, or a cyano group, provided that at least one of R1 and R2 represents a substituted or unsubstituted alkyl group containing 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group containing 7 to 30 carbon atoms, or a substituted or unsubstituted aryl group containing 6 to 30 carbon atoms;
• and R1 and R2 may link together and form a substituted or unsubstituted ring;
• to thereby prepare an optically active alcoholic compound represented by the general formula (3);
• wherein R1 and R2 are the same as defined above;
• which comprises treating the carbonyl compounds represented by the general formula (1) with a reducing agent prepared by treating an aluminum compound of the general formula (6);
• wherein R16, R17 and R18 are the same or different from each other and represent an alkyl group containing 1 to 20 carbon atoms, an aralkyl group containing 7 to 30 carbon atoms, an aryl group containing 6 to 30 carbon atoms, an alkoxyl group containing 1 to 20 carbon atoms, or a hydrogen atom;
• with an optically active bisalcohol derivative represented by the general formula (7);
• wherein R4, R5, R6, R7, R8, R9, R10 and R11 are the same or different from each other and represent a substituted or unsubstituted alkyl group containing 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group containing 7 to 30 carbon atoms, a substituted or unsubstituted aryl group containing 6 to 30 carbon atoms, a substituted or unsubstituted silyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted alkoxyl group containing 1 to 20 carbon atoms, a cyano group, an alkoxycarbonyl group containing 1 to 20 carbon atoms, a substituted or unsubstituted phosphorus atom, a substituted or unsubstituted sulfur atom, a halogen atom, or a hydrogen atom, and R4, R5, R6, R7, R8, R9R10 or R11 may link with each of them and form a substituted or unsubstituted, condensed ring;
• and with an alcoholic compound represented by the general formula (5);
• R3OH (5)
• wherein R3 represents a substituted or unsubstituted alkyl group containing 1 to 20 carbon atoms, or a substituted or unsubstituted aralkyl group containing 7 to 30 carbon atoms.