Hydrotalcite-supported palladium nanoparticles as catalysts for the Suzuki reaction of aryl halides in water

• Simple procedure for Suzuki reaction of arylhalides with phenylboronic acid in water.
• Catalyst: nanoparticles of Pd(0) over hydrotalcite in the absence of any ligand.
• Fluorobenzene can be coupled with phenylboronic acid in good yields.

A simple protocol for the Suzuki reaction of aryl halides with phenylboronic acid is proposed. The catalyst used consists of Pd(0) nanoparticles supported on an Mg/Al hydrotalcite. The catalyst was prepared and characterized in this work for the first time. Supported nanoparticles were obtained by depositing a Pd(II) salt onto the support and subsequently reducing it to Pd(0). The greatest novelties of the synthetic process are the use of a hydrogen donor (cyclohexene) to reduce the palladium precursor salt and that of water as solvent in the Suzuki reaction. Biphenyl conversions in the Suzuki reaction of phenylboronic acid with iodobenzene, bromobenzene and chlorobenzene were all excellent, and quantitative yields obtained within a very short time. Even fluorobenzene provided excellent results improving on many reported values for chelated Pd homogeneous catalysts. No homocoupling reaction was detected; also, although homogeneous and heterogeneous catalysis coexist, the catalyst can be recovered for reuse with no loss of activity.

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