Yoshinobu Yamane

Efficient synthesis of substituted 3-amino-3,4-dihydropyran-2-ones diastereo and enantioselective tandem Michael addition and lactonization between α,β-unsaturated ketones and glycine-derived silyl enolates using a chiral quaternary ammonium phenoxide

Chiral quaternary ammonium phenoxides are readily prepared from commercially available cinchona alkaloids and are employed as useful new asymmetric organocatalysts. The cinchonidine-derived catalyst is highly effective on Michael addition and successive lactonization between glycine-derived silyl enolates and α,β-unsaturated ketones. According to this asymmetric reaction, the corresponding 3-amino-3,4-dihydropyran-2-ones are formed in high yields with complete diastereoselectivities and excellent enantioselectivities.