Pronounced asymmetric amplification in the aldol condensation of Chan's diene promoted by a Ti(IV)/BINOL complex

A strong enhancement of the enantiomeric excess can be obtained by performing the enantioselective aldol reaction of Chan's diene in the presence of enantiornerically enriched Ti(O-i-Pr)(4)/BINOL catalysts derived from mixing pre-prepared solutions of enantiopure Ti(O-i-Pr)(4)/(R)-BINOL and Ti(O-i-Pr)(4)/(S)-BINOL at different concentrations. (C) 2004 Elsevier Ltd. All rights reserved.