An Efficient and General Microwave-Assisted Copper-Catalyzed Conia-Ene Reaction of Terminal and Internal Alkynes Tethered to a Wide Variety of Carbonucleophiles

This paper describes a highly efficient, microwave-assisted, Conia-ene reaction of alkynes bearing a stabilizing carbon nucleophile. The reaction, catalyzed by a commercially available copper catalyst, proceeds under neutral conditions and is generally applicable even to less reactive nucleophiles such as malonate, cyanoacetate, and sulfonyl-acetate derivatives. This copper-mediated cycloisomerization is also applicable to internal unactivated alkynes leading exclusively to the corresponding 5-membererd products having an E-olefinic chemistry.