Copper-Catalyzed Hydroamination of Alkynes with Aliphatic Amines: Regioselective Access to (1E,3E)-1,4-Disubstituted-1,3-dienes

Copper-catalyzed hydroamination of aromatic or heteroaromatic alkynes with cyclic secondary aliphatic amines undergoes generation of an enamine-type intermediate. The latter is transformed in situ via a coupling reaction with a second molecule of alkyne to afford regioselectively (1E,3E)-1,4-disubstituted-1,3-dienes with the formation of C-N, C-C, and C-H bonds.