Nanocrystalline Titania‐Supported Palladium(0) Nanoparticles for Suzuki–Miyaura Cross‐Coupling of Aryl and Heteroaryl Halides

Abstract

AbstractThe Suzuki cross‐coupling reaction of various aryl and heteroaryl halides with arylboronic and heteroarylboronic acids was studied using a titania‐supported palladium(0) catalyst at room temperature under air. The conversion and selectivity results obtained for many substrates were excellent and similar to those provided by more active or even homogeneous catalysts. The methodology is similarly effective using 2‐bromo‐3,4,5‐trimethoxybenzaldehyde as the coupling partner and gave products in good yield. Furthermore, it has been shown that it is useful for the synthesis of terphenyl and tetraphenyls. The catalyst is quantitatively recovered from the reaction by simple filtration and reused for a number of cycles without significant loss of activity. Inductively coupled plasma (ICP) mass‐spectrometric analysis of the filtrate from the reaction mixture demonstrated that the palladium metal hardly leached into the solution within the limits of the detector (1 ppm), thus suggesting that the present Suzuki–Miyaura reaction proceeded by heterogeneous catalysis.