Asymmetric synthesis of chiral β-hydroxy-α-amino acid derivatives by organocatalytic aldol reactions of isocyanoesters with β,γ-unsaturated a-ketoesters

摘要

The first organocatalytic asymmetric aldol reaction of isocyanoesters with various β,γ-unsaturated aketoesters has been described. Using cinchona alkaloid-derived bifunctional thiourea as the catalyst, chiral β-hydroxy-α-amino acid derivatives can be obtained in excellent yields and enantioselectivities (up to 95% yield and 92% ee) after acidic hydrolysis. This protocol provides a straightforward method to access multiple substituted β-hydroxy-α-amino acid derivatives with high enantiomeric purity.