One-Pot Synthesis of Propargylamines Using Ag(I)-Exchanged K10 Montmorillonite Clay as Reusable Catalyst in Water

Ag­(I)-exchanged K10 montmorillonite clay is found to be an efficient heterogeneous catalyst for the one-pot three-component coupling of terminal alkynes, amines, and aqueous formaldehyde (A³ coupling) to yield corresponding propargylamines in water. In all the cases, quantitative yields of the desired products are obtained. The catalyst is recovered by filtration and reused several times with only a slight decrease in its catalytic activity. This atom economical methodology does not require an additional co-catalyst or activator, and water is the only byproduct. Interestingly, the reaction can also be performed under solvent-free conditions in the case of aromatic and aliphatic aldehydes, along with formaldehyde, affording propargylamine derivatives in higher yields. A tentative mechanism is also proposed for this transformation