Enantioselective autoinduction in the aldol condensation of ethyl acetate and benzaldehyde: selective precipitation of an optically inactive Li–O-aggregate

Abstract

The influence of half an equivalent of optically active (–)-(S)-ethyl [3-²H]3-phenyl-3-hydroxypropanoate on the stereochemical course of the aldol condensation of ethyl acetate and benzaldehyde was studied; an enantioselective autoinductive effect on the formation of the second equivalent of hydroxyester of 18%(–100°C) was determined in favour of the opposite (+)-isomer; separate work-up of precipitated Li–O-aggregate revealed that the (+)–isomer is predominant in the solid phase [enantiomeric excess (e.e.) 68%]; the mother liquor is considerably enriched in the (–)-isomer (e.e. 59%).