Synthesis of enantiomerically enriched propargylamines by copper-catalyzed addition of alkynes to enamines

The first copper(I) bromide/ Quinap-catalyzed synthesis of enantiomerically enriched propargylamines by addition of alkynes to enamines is reported. Various functionalized terminal alkynes add smoothly to N-protected enamines to afford the corresponding amines in good to high yields and moderate to good enantiomeric excesses. The influence of the metal salt, the ligand, and the protecting group on the conversion, the reaction rate, and the stereoselectivity of the reaction are investigated. The scope of the reaction and further transformations of the resulting propargylamines (deprotection, Pauson-Khand reaction) are also described.