화학공학소재연구정보센터
Chemistry Letters, Vol.35, No.1, 56-57, 2006
Enantioselective synthesis of 3,4-dihydropyran-2-ones by chiral quaternary ammonium phenoxide-catalyzed tandem Michael addition and lactonization
Chiral quaternary ammonium phenoxides derived from cinchona alkaloids were easily synthesized and were effectively employed in the tandem Michael addition and lactonization between alpha,beta-unsaturated ketones and a silyl enolate derived from phenyl isobutyrate, and optically active 3,4-dihydropyran-2-ones were afforded in high yields with high enantiomeric excesses.