One-Pot Multi-Component Route to Propargylamines Using Zinc Oxide Under Solvent-Free Conditions

In this paper, commercially available ZnO was found to be a highly effective catalyst for three-component coupling reactions of alkynes, aldehydes/or ketone and amines (A3-coupling) via C-H activation. The reactions could be applied to both aromatic and aliphatic aldehydes. Nearly quantitative yields of the desired products were obtained in most cases. No co-catalyst or activator is required, and water is the only by-product in the reactions. Heterogeneous nature of the catalyst made it reusable for further chemical reactions.