Catalytic asymmetric alkynylation of α-imino ester: A versatile approach to optically active unnatural α-amino acid derivatives

Abstract

The catalytic asymmetric introduction of alkynyl functionality to α-amino acid derivatives was realized by the direct addition of terminal alkynes to α-imino ester in the presence of chiral Cu(I) complex under mild reaction conditions. Owing to the rich chemistry to which alkyne can be subjected, the present system provides a remarkably versatile tool for the construction of optically active α-amino acid derivatives. Good yields and enantiomeric excess values were achieved with an array of terminal alkynes and challenging, biologically active, unnatural α-amino acid derivatives could be conveniently obtained.