Catalyst retention utilizing a novel fluorinated phosphonium ionic liquid in Heck reactions under fluorous biphasic conditions

Abstract

A novel ionic liquid based on a highly fluorinated phosphonium cation was synthesized and its physicochemical properties were compared to its semi- and non-fluorinated analogue. The fluorinated ionic liquid was found to show a thermomorphic mixing behavior with organic solvents so that it could be applied as a substitute for volatile perfluorinated solvents in fluorous biphasic catalysis to achieve the recovery of perfluoro-tagged catalysts. Efficient immobilization of a perfluoro-tagged palladium catalyst in the fluorous ionic liquid phase was demonstrated for the Heck reaction as a model reaction of the widely applied Pd-catalysed Csingle bondC coupling reactions. The reaction of iodobenzene and methyl acrylate resulted in 83% yield after 20 runs proofing the efficient immobilization in the fluorophilic ionic liquid.