Copper-catalyzed amine-alkyne-alkyne addition reaction: an efficient method for the synthesis of gamma,delta-alkynyl-beta-amino acid derivatives.

A simple and efficient method for the synthesis of gamma,delta-alkynyl-beta-amino acid derivatives by a copper-catalyzed three-component amine-alkyne-alkyne addition reaction was developed. Various gamma,delta-alkynyl-beta-amino acid derivatives were synthesized in moderate to good yields in one step. With chiral prolinol derivatives employed as the amine component, excellent diastereoselectivities (up to >99:1 diastereomeric ratio (dr)) were obtained. The scope of the reaction and further transformations of the resulting amino acid derivatives, such as deprotection and cyclization are also described.