Palladium complexes grafted onto mesoporous silica catalysed the double carbonylation of aryl iodides with amines to give α-ketoamides

Abstract

A promising route for the double carbonylation of aryl iodide derivatives with secondary and primary amines to produce α-ketoamides is described using covalently immobilized palladium complexes on SBA-15 silica. Adequate adjustments of the different reaction parameters (temperature, CO pressure, nature of base, solvent, substrate…) to achieve optimal catalyst performance were made using PdCl₂(PPh₂)₂@SBA-15 as catalytic system. High conversions (up to 80%) and excellent selectivities (up to 96%) for the double carbonylated α-ketoamide products were obtained using K₂CO₃ as base, MEK or DMF as solvent and a 1 mol% [Pd] catalyst. We also demonstrated that two other palladium hybrid mesoporous materials can be alternatively used, namely PdCl₂(PCy₂)₂@SBA-15 and PdCl₂(PNP)@SBA-15, without loss of activity and selectivity. Finally, catalyst recycling of PdCl₂(PPh₂)₂@SBA-15 showed that the catalyst could be reused for up to 3 cycles without affecting catalyst performance.