A New Polymer Supported Palladium Complex as Active, Air Stable and Recyclable Catalyst for Carbon-Carbon Bond Forming Reactions

摘要

The polymer supported palladium catalyst (Pd-pol) obtained by reaction between Pd(AAEMA)_2, [AAEMA~-= deprotonated form of 2-acetoacetoxy(ethylmetacrylate)] ethyl methacrylate (comonomer) and ethylene glycol dimethacrylate (cross-linker) has been used in the Heck coupling of aryl iodides and bromides with various olefins. Under phosphine-free conditions and using two equivalents of base, the catalyst, which is air stable and resistant to water washings, could be recycled at least five times without loss of activity and selectivity. The analysis of the mother liquors at different conversion values indicates that little amount of palladium is leached out during each cycle and that the catalytic phenomenon is mainly homogeneous.