Synergistic Tri‐Metallic Heterogeneous Nanocatalyst for Ligand‐Free Oxidative Homocoupling of Terminal Alkynes

ABSTRACT

Herein, we report the synthesis of a carbon‐supported palladium‐based tri‐metallic nanocatalyst (cat‐G) and its successful application to facilitate the oxidative homocoupling of aromatic and aliphatic terminal alkynes. The catalyst contains significantly less amount of total metal content (20%) and was characterized using x‐ray photoelectron and energy‐dispersive x‐ray spectroscopies, x‐ray diffraction, thermogravimetric analysis, and transmission electron microscopy. Our implementation of EtOH as a solvent medium along with minimal catalyst loading for the synthesis of symmetrical 1,3‐diynes under aerial oxidation without the aid of any ligand unveils simple and milder reaction conditions for C(sp)–C(sp) coupling reactions. The protocol displays a broad substrate scope, and the catalyst possesses simple recovery along with moderate recyclability up to five catalytic cycles.