Oxime Palladacycle Supported on Magnetic Meoporous Silica: An Efficient Catalyst for Copper‐Free Acyl Sonogashira Reaction

Abstract

The catalytic activity of the supported bis(oxime palladacycle) catalyst was evaluated in the acyl Sonogashira reaction. The reaction conditions, such as solvent, base, and palladium content, were screened to achieve the best catalytic performance. Tetrahydrofuran (THF) solvent, triethylamine (Et3N) base, and the reaction temperature of 110°C were found to be ideal for achieving high yields of the desired products. Furthermore, a catalyst loading of only 0.22 mol% palladium was sufficient to achieve good conversion. Broad ranges of aryl acetylenes and benzoyl chlorides were successfully coupled to give the desired acetylenic ketones. The reaction appeared to proceed efficiently using a small amount of catalyst. The magnetic property of the catalyst allowed for easy separation using an external magnet. The catalyst was stable and reused for multiple reaction runs without a significant deactivation. After seven cycles, the catalyst maintained over 90% of its initial catalytic activity.