Phosphine-Free Tetradentate Salicylaldimine Ligand Complexed with Palladium: First Application in Heck Reactions

Abstract

Heck reactions were carried out using phosphine-free tetradentate salicylaldimine ligand complexed with PdCl₂ under mild reaction conditions, short reaction time, and low palladium loading. All aryl iodides underwent coupling reactions with olefins, giving corresponding trans-products, with good to excellent yields, whereas aryl bromides gave very poor yields and aryl chlorides failed to react.

GRAPHICAL ABSTRACT

Keywords:

• Aryl halides
• Heck reactions
• olefins
• palladium chloride
• salicylaldimine

Notes

^a Reaction conditions: Iodobenzene (5 mmol), methyl acrylate (10 mmol), K₂CO₃ (5 mmol), 1, solvent (10 mL), reaction time 4 h, in a sealed tube under N₂ atmosphere.

^b Isolated yield.

^a Reaction conditions: Aryl halide (5 mmol), olefin (10 mmol), K₂CO₃ (5 mmol), 1 (0.1 mol%), DMF (10 mL), temperature 80 °C, reaction time 4 h, in a sealed tube under N₂ atmosphere.

^b Isolated yield.

The present affiliation for Rahul S. Kalhapure is Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.

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