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Keywords:

  • cross-coupling reactions;
  • heterogeneous palladium catalysts;
  • multi-component reaction;
  • one-pot synthesis;
  • stilbenes;
  • Suzuki/Heck sequence

Abstract

The synthesis of (E)-stilbenes was performed following a one-pot Suzuki/Heck sequence through the use of potassium vinyltrifluoroborate. The combination of heterogeneous palladium/silica (Pd/SiO2) catalyst with potassium phosphate monohydrate (K3PO4⋅H2O) as base resulted in useful to good isolated yields regardless of the ortho-, meta- or para-substitution of the aryl halides employed. In a sustainable approach, we found that bio-sourced 1,3-propanediol could advantageously replace N-methylpyrrolidone (NMP) as similar yields were obtained. Moreover, the reactivity gap between aryl iodides and bromides resulting from the use of 1,3-propanediol allowed an efficient multi-component approach toward the synthesis of (E)-stilbenes. Furthermore, this heterogeneous catalyst was found to be extremely robust despite the use of aerobic conditions and was successfully re-used over several cycles.