s Carbonylation of Aryl Halides in the Presence of Heterogeneous Catalysts

Palladium-catalyzed carbonylation in the presence of organic and organometallic nucleophiles serves as a powerful tool for the conversion of aryl/alkenyl halides or halide equivalents to carbonyl compounds and carboxylic acid derivatives. To circumvent the difficulties in product separation and recovery and reuse of the catalysts, associated with homogeneous reactions, supported counterparts of the homogeneous palladium catalysts were developed. The review intends to summarize the huge development that has been witnessed in recent years in the field of heterogeneous carbonylation. A great plethora of supports, organic modifiers on solid surfaces stabilizing metal particles, transition metal precursors, as well as alternative sources for CO was investigated. In most cases, careful optimization of reaction conditions was carried out. Besides simple model reactions, the synthesis of carbonyl compounds and carboxylic acid derivatives from substrates with different functionalities was performed. In some cases, causes of palladium leaching were clarified with detailed investigations. The advantages of immobilized catalysts were shown by several examples. The possibility of catalystrecycling was proved besides proving that metal contamination of the products could often be kept below the detection limit. At the same time, detailed investigations should be carried out to gain a better insight into the real nature of these processes.