Green‐Synthesized Nickel Nanoparticles on Reduced Graphene Oxide as an Active and Selective Catalyst for Suzuki and Glaser‐Hay Coupling Reactions
Murugan Karthik, Nainamalai Devarajan, Pavithara Kanagaraj, Saravana Ganesan Nagappan, Palaniswamy Suresh
Abstract
A mild and benign methodology to syntheses biaryls and 1,3‐diynes has been demonstrated using the nickel nanoparticles supported on reduced graphene oxide (RGO‐Ni) as a heterogeneous catalyst which is prepared using green reagents. A series of substituted biaryls and 1,3‐diynes has been synthesised in good to excellent yields through C‐C homocoupling reaction of arylboronic acids and terminal alkynes respectively using 1,4‐dioxane as a benign solvent. The present ligand‐free catalytic system proceeds smoothly under mild conditions, avoids noble and stoichiometric metal reagents and tolerates sensitive functional groups. Also has a wide substrate scope and feasible with other nitrogen and sulphur containing heteroaryl boronic acids. Hot filtration test unambiguously proves the true heterogeneity of the catalyst and which support for the further reusability of the catalyst for several times without any change in the activity. The easy preparation and simple magnetic separation, stability and reusability reveal that as‐prepared RGO‐Ni as a versatile catalyst for the synthesis of polyaromatic compounds both in academia and industries. Highlights Green‐synthesized RGO‐Ni nanocomposite used as a heterogeneous catalyst for Suzuki type (C‐C) and Glaser–Hay (C ≡ C) homocoupling coupling reactions. Ligand‐free catalytic system and avoids noble and stoichiometric metal reagents Short reaction time with a minimum catalyst (nickel) loading RGO‐Ni nanocomposite is highly stable, reusable, and magnetically retrievable