Sterically enhanced 2-iminopyridylpalladium chlorides as recyclable ppm-palladium catalyst for Suzuki-Miyaura coupling in aqueous solution

Sterically hindered 2-iminopyridine derivatives and their palladium chlorides complexes are designed and prepared, which efficiently promote the Suzuki-Miyaura coupling (SMC) reaction in aqueous solution. Besides the good to excellent yields and broad substrate scope, these catalysts can be reused for at least four new batches of the substrates. Spontaneous separation of coupling products in the aqueous reaction medium is the additional striking feature of this catalytic process. Furthermore, catalytic performance of palladium complexes bearing the azo-bridged phenyl groups was greatly influenced by the UV irradiation due to the cis/trans photoisomerization of azo unit of the catalysts. In conclusion, titled palladium complexes provide a green, sustainable, cost-effective, and convenient process to synthesize SMC products at multi-gram-scale reaction.

Automated summary

The sterically hindered 2-iminopyridine derivatives and their palladium chlorides complexes efficiently catalyze the Suzuki-Miyaura coupling reaction in aqueous solution, with good substrate scope and reusability for multiple batches. The spontaneous separation of coupling products in the aqueous medium adds to the process's appeal, while the catalytic performance can be significantly influenced by UV irradiation due to the photoisomerization of the catalysts' azo units. Overall, these titled palladium complexes offer a green, sustainable, cost-effective, and convenient method for synthesizing SMC products at a multi-gram scale.