Palladium Nanoparticles on Covalent Organic Framework Supports as Catalysts for Suzuki-Miyaura Cross-Coupling Reactions

Suzuki-Miyaura cross-coupling (SMC) reaction by palladium (Pd) catalysis is widely used in cross-coupling chemistry synthesis for C-C bond formation, yet the biaryl products are generally lacking halo substituents due to highly active palladium species. Suitable catalysts according to this property for the regionselective SMC synthesis of biaryl derivatives with halo substituents did not receive due and sufficient attention. Here, we report the facile synthesis of a covalent organic frameworks (COFs)supported nanoparticles Pd catalyst that can region-selectively catalyze the SMC reaction of aryl boronic acids and aryl halides, especially with halogenated aryl boronic acids. The methodology exhibits mild operating conditions, broad functional group tolerance, and environmental friendliness and can be strategically applied for cross-coupling scenarios governed by sequential transition metal catalysts to build with or without a halo-substituted moiety. The Pd/COF-SMC nanoparticles catalysts are stable and reusable and succeed in synthesizing halo-substituted biaryl products in excellent yield, which avoids the homocoupling of halogenated aryl boronic acid. The most outstanding advantage is the precise regulation of nanoparticles Pd activity with the well-designed COF ligand