Covalent Triazine Frameworks Supported Palladium For Selective Double Carbonylation Of Aryl Iodides

The ?-ketoamides with unique double carbonyl structure can be used as a kind of medicine intermediate and organic synthesis raw material,which has been widely studied by researchers.The palladium-catalyzed double carbonylation of aryl halides and amine compounds is an important methodology for the preparation of ?-ketoamides.Although this method is effective,however,it generally requires organic phosphorus ligands or the high pressure of carbon monoxide and palladium catalyst is difficult to recycle,these conditions severely limit the practical application of palladium catalyzed ?-ketoamides.Therefore,the development of an efficient,easily synthesized,recyclable catalyst under ambient pressure of carbon monoxide and without organic ligands,which can highly selective obtain the ?-ketoamides,is urgently required.Covalent organic framework(COFs)as a new kind of porous material has attracted widespread attention for its large specific surface area,low density of skeleton,high thermodynamic stability,controllable physical and chemical properties,easy functionalized.What's more,the materials have important application in the field of gas storage,separation,catalysis,sensors,photoelectric and biological medicine.This thesis reports that a facile preparation of the hybrid Pd/CTFs catalyst using the impregnation-reduction method which Pd particles are highly dispersed in CTFs.The Pd/CTFs catalyst can selectively catalyze double carbonylation of aryl halides to build ?-ketoamides in the presence of carbon monoxide.The specific content is as follow.The structure-stable covalent triazine-base frameworks(CTFs)are prepared in the presence of trifluoromethanesulfonic acid via the nitrile cyclotrimerisation at room temperature.The desinged CTFs contain a large amount of nitrogen,which is beneficial to coordinate with palladium and stabilize palladium nanoparticles.The CTFs can provide a micro-reactor through its unique pores which can adsorb carbon monoxide and organic substrates and accelerate the catalytic process.Double carbonylation of aryl iodides with amines under atmospheric pressure of carbon monoxide,catalyzed by Pd/CTFs without the assistance of organic phosphine ligands,leads to the highly selective synthesis of a-ketoamides.Our strategy can reduce the cost of experiment and operation steps and avoid effectively the pollution of the environment caused by phosphine ligands.Single and double carbonylation reaction can be easily controlled by temperature.The double carbonylation products are the main products at 70 ? and the mono carbonylation products are the main products at 100 ?.What's more,the catalyst has good adaptability and good cycle performance.