Silver Catalysed A³-Coupling Reactions in Phenylacetic Acid/Alkylamine N-Oxide Eutectic Mixture Under Dielectric Heating: an Alternative Approach to Propargylamines

The development of alternative benign reaction conditions to perform multicomponent reactions is an interesting and desirable strategy to increase the sustainability of organic synthesis. In this paper, we report a new version of A3-coupling MCR for the preparation of differently substituted propargylamines starting from aldehydes, alkynes and amines in an acidic DES as reaction media, under dielectric heating, and in the presence of a tetraaza-macrocyclic silver complex as catalyst. The reaction scope is broad in terms of aldehydes partners. Electron-rich phenylacetylenes are the more reactive alkynes partners, whereas the nature of the amine is the more serious limitation as only secondary cyclic amines are tolerated.