Direct Formation of N-Acylated Amino Acid Derivatives via Nucleophilic Addition to N-Acylimino Esters Using a Polymer-Supported Amine and Scandium Triflate

摘要

N-Acylated amino acid derivatives are often observed in biologically important compounds such as peptides, ceramides, etc. The use of α-imino esters provides a convenient method for the preparation of N-acylated amino acid derivatives (eq 1). After nucleophilic addition to α-imino esters, the protective group of the amino moieties are removed, and then the amino groups are acylated. More conveniently, reactions of N-acylimino esters would give N-acylated amino acid derivatives directly (eq 2). However, N-acylimino esters are unstable and their use in organic synthesis has been rather limited. In this paper, we describe a new method for the preparation of N-acylated amino acid derivatives via nucleophilic addition to N-acylimino esters using polymer-supported amine and scandium catalysts. The method is simple and provides a convenient way for the preparation of N-acylated amino acid derivatives.