Pd-Catalyzed C-C Cross-Coupling Reactions within aThermoresponsive and pH-Responsive and Chelating PolymericHydrogel

摘要

A porous, thermoresponsive and pH-responsive, and chelating hydrogel of poly(N-isopropylacrylamide)-co-poly[2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxypropyl ester] (PNIPAM-co-PMACHE)is proposed as both a reaction medium and the Pd catalyst support for organic synthesis. Organic synthesiswithin the PNIPAM-co-PMACHE hydrogel has three merits. First, organic reactions such as Suzuki andHeck reactions within the hydrogel can be accelerated due to the enriched Pd catalyst and reactantswithin the hydrogel by the reversible deswelling/swelling. Second, organic synthesis within the PNIPAM-co-PMACHE hydrogel, which holds about ～300 times of water and is similar to the environmentallybenign reaction medium of water, can be performed efficiently without surfactant or cosolvent beingadded. Third, the PNIPAM-co-PMACHE hydrogel itself and the therein-immobilized Pd catalyst can beeasily recycled since the hydrogel/Pd composite can reversibly swell/deswell.