Synthesis of Cu@Fur-SBA-15 as a novel efficient and heterogeneous catalyst for promoting A3-coupling under green and mild reaction conditions

A novel and heterogeneous catalyst, Cu@Fur-SBA-15, was designed and synthesized through multi-functionalization of Cl-SBA-15 with thiosemicarbazide and furfural and immobilization of copper species. The hybrid system was then fully characterized by using SEM/EDX, XRD, BET, ICP-AES, TGA and FTIR and applied as a heterogeneous catalyst for promoting three-component A3-coupling reaction of alkyne, aldehyde and amine under solvent-free condition at ambient temperature. The results indicated excellent catalytic activity of the catalyst which was superior to many of previously reported protocols. Notably, the catalyst was reusable and could be recovered and reused up to four reaction runs. The hot filtration test and ICP-AES analysis confirmed negligible copper leaching, indicating heterogeneous nature of the catalysis. The analysis of the reused catalyst established the stability of the catalyst upon reusing up to four reaction run. Broad substrate scope, simple work-up procedure and short reaction times are other advantageous of this mild and green protocol