Polydopamine supported palladium nanoparticles: Highly efficient catalysts in Suzuki cross-coupling and tandem Suzuki cross-coupling/nitroarene reductions under green reaction conditions

摘要

The application of an easily prepared and highly active polydopamine-supported Pd nanoparticles catalyst in Suzuki cross-couplings and tandem Suzuki cross-coupling/catalytic transfer hydrogenation sequences under green reaction conditions is described. In Suzuki cross-couplings between aryl bromides and arylboronic acids Pd concentrations down to ppm levels could be used, while reactions were completed within minutes. Heteroaryl bromides needed somewhat longer reaction times but could be transformed under otherwise identical conditions. The efficiency of the Suzuki cross-couplings made them compatible with the mechanistically different catalytic nitroarene transfer hydrogenations, yielding valuable biphenyl aniline products in a mild, one-pot tandem fashion. The influence of reaction time, temperature and Pd particle size on the catalyst efficiency and recyclability is also examined. (C) 2018 Elsevier Inc. All rights reserved.