The silver salt of 12-tungstophosphoric acid: an efficient catalyst for the three-component coupling of an aldehyde, an amine and an alkyne

A three-component coupling of an aldehyde, an alkyne and an amine to prepare propargylamines was performed using the silver salt of 12-tungstophosphoric acid (Ag₃PW₁₂O₄₀) as a heterogeneous catalyst under mild reaction conditions in the absence of any co-catalyst. A variety of aldehydes and amines were converted to the corresponding propargylamines demonstrating the versatility of the reaction. The Ag₃PW₁₂O₄₀ (AgTPA) catalyst was recovered quantitatively by a simple filtration and reused several times.