Copper Nanoparticles Catalyzed Three-component Coupling Of Alkyne, Dihalomethane And Amine For The Synthesis Of Propargylamine

In this paper, we report the three-component coupling of alkyne, dihaloalkane, and amine (AHAcoupling) for the synthesis of propargylamine using copper nanoparticle under mild condition.Compared with the reported methods, the catalytic system has many advantages, such as cheapermetal catalyst used, more wild reaction condition, good functional group tolerance, at the most, byusing mono-solvent the operation is more convenient and the catalyst is easy to recycle.With copper nanoparticle as catalyst, caesium carbonate as base, and dihaloalkane as solvent,this catalytic system shows good catalytic activities to lots of substrates We found that botharyl-alkynes and alkyl-alkynes were active in this reaction, but aryl-alkynes gave better yields of thepropargylamine than alkyl-alkynes. Cyclic, heterocyclic, and acyclic aliphatic secondary amines gaveexcellent yields of products under the standard reaction conditions. However, no AHA couplingproduct was isolated with primary amines.Furthermore, a “hot separation” experiment was designed to investigate the reaction mechanism,the result suggested that the reaction minght be carried on the surface of nanoparticles rather than bythe presence of soluble copper ions in the solution. Than a plausible reaction mechanism for theformation of propargylamines was proposed.Finally, the recycling of copper nanoparticle catalyst and several supported copper nanoparticleswas evaluated. We found that the catalyst could be recycled, and reused over five cycles withoutdeactivation.