Suzuki–Miyaura cross-coupling reaction between aryl halides and phenylboronic acids over gold nano-particles supported on MgO (or CaO) and other metal oxides

Formation of biphenyls with high yields and high turnover rates comparable to or even higher than that achieved using ligand-free-supported Pd catalysts reported earlier could be accomplished using ligand-free nano-gold particles supported on MgO or CaO in the Suzuki–Miyaura cross-coupling reaction. [Display omitted] ► Au/MgO (or CaO, BaO, or SrO) showed high catalytic activity in the Suzuki–Miyaura coupling reaction. ► The coupling activity of nano-gold catalyst was strongly influenced by the nature of metal oxide support. ► The presence of K2CO3 (base) and DMF (solvent) is must for high product yield. ► The Au/MgO showed high activity and excellent reusability in the coupling reaction. ► The Au/MgO is ligand-free and also less costly than commonly used Pd-based catalysts. Gold nano-particles-supported alkaline earth metal oxides, particularly MgO or CaO, show high catalytic activity in the Suzuki–Miyaura cross-coupling reaction in the presence of K2CO3 and DMF (as a solvent). The catalytic activity is strongly influenced by the nature or type of metal oxide support (viz. alkaline earth oxide, Group IIIA metal oxide, transition metal oxide, or rare earth oxide actinide oxide). It is also strongly influenced by the nature of aryl halide (aryl iodide, bromide, chloride, or fluoride), amount of K2CO3 in the reaction mixture and catalyst calcination temperature. Influence of reaction parameters viz. temperature and time and different substituents in aryl halides and/or phenylboronic acids on the biphenyl product yield in the reaction over Au/MgO catalyst has also been investigated. The catalyst showed excellent reusability in the reaction. Moreover, it is ligand-free and also has much lower cost than the commonly used homogeneous and heterogeneous Pd catalysts.