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

Age(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 (A(3) 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.