Pd-Aminoclay Nanocomposite as an Efficient Recyclable Catalyst for Hydrogenation and Suzuki Cross Coupling Reactions

A highly water dispersible Pd-aminoclay nanocomposite is found to be effective catalytic system for the hydrogenation of alpha,beta-unsaturated carbonyl compounds and Suzuki coupling reactions in aqueous media. The catalytic hydrogenation of alpha,beta-unsaturated carbonyl compounds proceeds at room temperature to afford the corresponding products in excellent yields with high chemoselectivity. The cross coupling of aryl bromides and iodides with aryl boronic acids proceeds efficiently under aqueous conditions at 90 degrees C to afford the corresponding biaryls in excellent yields with high selectivity. The Suzuki reaction proceeds smoothly even in the absence of external base due to the basic nature of the catalyst support. The catalyst could be easily recovered and recycled three times without a significant loss of activity in hydrogenation and Suzuki cross coupling reactions.