Synthesis of 4-Substituted Styrene Compounds via Palladium-Catalyzed Suzuki Coupling Reaction Using Free Phosphine Ligand in Air

Abstract

The air-stable and easy to prepare nonsymmetric Schiff base ligands have been synthesized and proven to be efficient ligands for Suzuki cross-coupling reaction between aryl bromides and arylboronic acids using PdCl₂(CH₃CN)₂ as palladium source under aerobic conditions. The coupling reaction proceeded smoothly using N-[(3,4-dimethoxyphenyl)methylene]-1,2-benzenediamine (L₃) as ligand under mild conditions to provide 4-substituted styrene compounds in good yields.

Keywords:

• 4-Substituted styrene compounds
• Schiff base ligands
• Suzuki
• synthesis

Notes

^a Reaction conditions: p-bromostyrene (0.50 mmol), phenylboronic acids (0.75 mmol), PdCl₂(CH₃CN)₂ (0.5% mmol), base (1.5 mmol), solution (2.0 mL), temperature 80°C, reaction time 10 h.

^b Isolated yield.

^a Reaction conditions: aryl bromides (0.50 mmol), arylboronic acids (0.75 mmol), L₃ (0.75 mmol%), PdCl₂ (CH₃CN)₂ (0.50 mmol%), base (1.50 mmol), toluene (2.0 mL), 80°C, reaction time 10 h.

^b Isolated yield.