Palladium supported on bis(indolyl)methane functionalized magnetite nanoparticles as an efficient catalyst for copper-free Sonogashira-Hagihara reaction

• A novel catalyst using Pd supported on bisindolyl functionalized Fe3O4 is synthesized.
• The catalyst was characterized using different analytical methods.
• The catalyst was applied for Sonogashira reactions of aryl halides (Cl, Br, I) under air.
• The Sonogashira reaction was performed under Copper and Phosphane free conditions.
• The catalyst was successfully recycled for seven consecutive runs by an external magnet.

A novel heterogeneous catalyst based on palladium nanoparticles supported on 3,3′-bisindolyl(4-hydroxyphenyl)methane functionalized magnetite (Fe3O4) nanoparticles was synthesized, characterized and used as catalyst for Sonogashira-Hagihara reaction. The alkynylation of a variety of aryl iodides and aryl bromides with terminal alkynes was carried out at 60 °C under copper and phosphane-free conditions using N,N-dimethyl acetamide as solvent, DABCO as base and low Pd loadings (0.18 mol%) under air. In the case of aryl chlorides, the reaction was carried out at 120 °C in the presence of tetra-n-butylammonium bromide (TBAB) and 0.36 mol% of Pd catalyst. The heterogeneous palladium catalyst introduced in this study is recoverable by an external magnet and it can be used for seven consecutive runs without a significant loss in catalytic activity.

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