Organic group decorated heterogeneous Pd complex on mesoporous silica toward catalytic allylation in aqueous media

The use of water as a reaction solvent is ideal for green chemistry. However, carrying out catalytic reactions with transition metal catalysts in aqueous media is challenging. To enhance the scope of transition-metal-catalyzed allylation reactions in aqueous media, a series of Pd diphosphine complexes co-immobilized with organic groups onto mesoporous silica (MS) supports was synthesized. The synthesized catalysts were characterized via FT-IR, XAFS, and hydrophobicity determined via contact angle measurements. The newly synthesized catalyst demonstrated improved catalytic allylation performance in water. Aqueous catalytic allylation between allyl methyl carbonate and ethyl acetoacetate produced disubstituted product yields greater than 99%. Moreover, an MS pore size of 3.1 nm and phenyl/Pd ratio of 15 demonstrated the highest activity among the synthesized catalyst library. The results significantly expand the toolkit of transition-metal-catalyzed reactions in aqueous media; we believe they will have far-reaching consequences owing to the wide use and scope of allylation re-action in academia as well as industry.

Automated summary

The use of water as a reaction solvent is ideal for green chemistry, but carrying out catalytic reactions with transition metal catalysts in aqueous media is challenging. To enhance the scope of allylation reactions in water, a series of Pd diphosphine complexes co-immobilized with organic groups onto mesoporous silica supports was synthesized. The newly synthesized catalyst demonstrated improved catalytic allylation performance in water, expanding the toolkit of transition-metal-catalyzed reactions in aqueous media. The results have far-reaching consequences in academia and industry due to the wide use and scope of allylation reaction.