Suzuki-Miyaura Coupling Reaction Using Palladium Nanoparticles Immobilized on SPB

Key words

palladium - Suzuki-Miyaura coupling - Heck reaction - nanoparticles

Significance

Palladium nanoparticles immobilized on spherical polyelectrolyte brushes (Pd@SPB) were synthesized and found to promote the Suzuki-Miyaura cross-coupling reaction. Thus, the spherical polyelectrolyte brushes having the (2-methylpropenyloxyethyl)trimethylammonium cation were prepared according to the reported procedures (Y. Mei, G. Sharma, Y. Lu, M. Ball­auff Langmuir 2005, 21, 12229). The reaction of SPB with Na₂PdCl₄ followed by reduction with NaBH₄ gave the palladium nanoparticles immobilized in the SPB matrix (Pd@SPB). The Suzuki-Miyaura coupling reaction of aryl halides with phen­ylboronic acid was carried out in the presence of Pd@SPB (0.09 mol% Pd) in H₂O-THF to give the corresponding biphenyls in good yield (14 examples, 50-94% yield).

Comment

Recently, the authors have reported the preparation of platinum nanoparticles immobilized on SPB (Pt@SPB), which was found to be an effective catalyst for the reduction of p-nitrophenol with NaBH₄. The present report described that the palladium nanoparticles (Pd@SPB) exhibited good activity for the Suzuki-Miyaura coupling reaction. This catalyst was recovered and reused for four times without any loss of catalytic activity. Heck reaction using the palladium nanoparticles (Pd@SPB) was also described.