Pd-TPPTS catalyzed Mizoroki–Heck coupling in halogen-free ionic liquids [Rmim][p-CH3C6H4SO3]

A highly efficient system composed of Pd-TPPTS [TPPTS: trisodium salt of tri(m-sulphonylphenyl)phosphine] and halogen-free ionic liquid ([Rmim][p-CH3C6H4SO3], R = methyl, ethyl, n-butyl, n-hexyl, n-octyl, n-dodecyl) has been established for Heck coupling of aryl halides with styrene. Most of the investigated substrates could give the complete conversions (> 95%) with the catalyst of 1 mol% at 110 °C. The resulting products can be easily separated from the ionic liquids by simple liquid-liquid extraction, and the catalyst immobilized by ionic liquids can be consecutively run five times without significant loss in catalytic activity.

Graphical AbstractWater-soluble Pd-TPPTS carried out the highly efficient Mizoroki–Heck coupling of aryl halide with styrene in [Rmim][p-CH3C6H4SO3].Figure optionsDownload as PowerPoint slideHighlights
► Water-soluble ionic liquid [Rmim][p-CH3C6H4SO3] was originally used for Heck coupling.
► The system showed the high reactivity and selectivity with the low palladium loading of 1 mol%.
► Catalyst was recovered easily and recycled.