Oxotitanium complexes useful as asymmetric reaction catalysts particularly for producing beta-hydroxy ketones or alpha-hydroxy carboxylic acid esters.

摘要

A novel oxotitanium complex represented by general formula (I) is disclosed: <CHEM> wherein R<1> and R<2> may be hydrogen, lower alkyl, lower alkoxy, halogen, phenyl, substituted phenyl, trialkylsilyl, monoalkyldiphenylsilyl, dialkylmonophenylsilyl, triphenylsilyl, substituted triphenylsilyl, or lower alkoxycarbonyl; R<1> and R<2> may be bonded to form a hydrocarbon ring with the ring carbon atoms; R<3> and R<4> may be different and each represents hydrogen, lower alkyl, lower alkoxy, benzoyl, benzenesulfonyl, or halogen; R<3> and R<4> may be bonded to form a hydrocarbon ring with the ring carbon atoms; and n is 1 or 2. The novel oxotitanium complex is particularly useful as an asymmetric reaction catalyst in glyoxylate-ene or aldol reactions, and processes for producing beta -hydroxy ketones or alpha -hydroxy carboxylic acid esters in its presence are also disclosed.