Development of Noncovalent Supported Ionic Liquid Phase Catalyst (SILPC) for Liquid-Phase Reaction as a Benign and Sustainable Protocol to Immobilize Homogeneous Catalyst

Homogeneous catalysts were immobilized to the pores of amorphous inorganic supports with the aid of an ionic liquid as Pd-, Cu-, and Ru-supported ionic liquid phase catalyst (SILPC), which is a benign method to immobilize sophisticated but unstable homogeneous catalysts so far difficult to load in an inorganic support by simple impregnation method. By immobilizing as a SILPC, sustainability and reactivity of catalysts increased in Mizoroki-Heck reaction, Suzuki-Miyaura reaction, Huisgen [3+2] cycloaddition (click reaction) without external ligand in aqueous media and ambient atmosphere, and olefin metathesis reactions. In addition, palladium was immobilized on nano-silica gel dendrimer as a nano-SILPC, which was highly active to Suzuki-Miyaura reaction. Moreover, MacMillan imidazolidinone organomolecular catalyst was immobilized as a Mac-SILPC to enable sustainable asymmetric Diels-Alder reaction. SILPCs could be repeatedly used by filtration.