Synthesis Of Mesoporous MCM-41 Or Magnetic Nanoparticles Supported Palladium Complexes And Their Applications In The Construction Of N-Heterocycles And Aldehyde-Ketone Compounds

In recent years,the synthesis of carbonyl compounds and N-heterocyclic compounds via palladium-catalyzed carbonylation has attracted much attention.However,homogeneous palladium complexes are difficult to separate from the reaction mixture and can not be reused,the target products are easily contaminated by palladium species,which greatly limited their practical applications.Therefore,it has important theoretical and practical significance to develop heterogeneous palladium catalysts with high activity and excellent recyclability and apply them to the carbonylation reaction.In order to solve the problem that expensive homogeneous palladium catalysts are difficult to separate from the product and can not be recycled,homogeneous palladium catalysts are commonly immobilized on the surface of solid supports by chemical bonding because the supported palladium catalysts are easily separated and recyclable while maintaining their catalytic activity.In this dissertation,a series of palladium complexes immobilized on mesoporous material MCM-41 and magnetic Fe₃O₄ nanoparticles have been designed and synthesized based on the excellent properties of mesoporous material MCM-41 and magnetic Fe₃O₄ nanoparticles as the supports for immobilizing transition-metal catalysts.The structures of these heterogeneous palladium complexes have been characterized by different analytic techniques.The applications of these palladium catalysts in the carbonylation reactions for the synthesis of aldehydes,ketones and N-heterocyclic compounds have been investigated.The research works are divided into seven aspects as follows:?1?The carbonylative cyclization of 2-aminobenzamides with aryl iodides catalyzed by an MCM-41-immobilized bidentate phosphine palladium?II?complex[MCM-41-2P-Pd?OAc?₂]has been studied.A variety of quinazolinone derivatives have been obtained in good yield via the carbonylative cyclization reaction from2-aminobenzoamides and aryl iodides in N,N-dimethylformamide?DMF?at 120oC under 10 bar of carbon monoxide,using 2 mol%of MCM-41-immobilized bidentate phosphine palladium?II?complex as catalyst and 1,8-diazabicycloundec-7-ene?DBU?as base.The new heterogeneous palladium catalyst can be recycled up to 8 times and its activity remains unaltered,which providing a novel and practical method for the synthesis of quinazolinone derivatives.A possible reaction mechanism has been proposed.?2?The carbonylative cyclization of 2-iodoanilines,amines,methyl ortho-formate and CO catalyzed by an MCM-41-supported bidentate nitrogen palladium?II?complex[MCM-41-2N-Pd?OAc?₂]has been investigated.The results show that the four-component carbonylative cyclization reaction proceeds smoothly in toluene at 110oC under 10 bar of carbon monoxide by using a phosphorus-free heterogeneous palladium?II?complex[1.5 mol%MCM-41-2N-Pd?OAc?₂]as catalyst and N,N-diisopropylethylamin?DiPEA?as base,yielding a wide variety of 4-?3H?-quinazolinone derivatives in high yield.This heterogeneous palladium catalyst can be reused at least 10 times with almost consistent catalytic activity.The present work has provided a novel and green method for the preparation of 4?3H?-quinazolinone derivatives from readily available starting materials.?3?The hydroformylation of aryl iodides with formic acid as CO source catalyzed by an MCM-41 supported bidentate phosphine palladium?II?complex[MCM-41-2P-Pd?OAc?₂]has been studied.The hydroformylation of aryl iodides with formic acid as CO source in the presence of iodine and triphenylphosphine as promoters proceeds smoothly under mild conditions,providing a variety of aromatic aldehydes in high yield.In addition,this heterogeneous palladium catalyst can be recycled at least 8 times without significant loss of activity,which providing a new,efficient and convenient route for the synthesis of various aromatic aldehydes.A possible reaction mechanism has been proposed.?4?The carbonylative cross-coupling reaction of aryl halides with triorgano-indiums catalyzed by an MCM-41-supported Schiff base palladium?II?complex[MCM-41-N,N-Pd?OAc?₂]has been studied.The carbonylative cross-coupling of aryl halides with triorganoindiums proceeds smoothly in the presence of 1.0 mol%MCM-41-N,N-Pd?OAc?₂ in THF at 68oC.A wide variety of asymmetrical ketones have been prepared in high yield.This heterogeneous palladium catalyst[MCM-41-2P-Pd?OAc?₂]can be recycled up to 8 times and its activity remains unchanged,which providing a new and practical method for the synthesis of asymmetric ketones under phosphine-free conditions.?5?The four-component carbonylative addition reaction of aryl iodides,alkynes,amines and CO catalyzed by an MCM-41 supported bidentate phosphine palladium?II?complex[MCM-41-2P-Pd?OAc?₂]has been investigated.By optimizing the reaction conditions,the examination of the substrate scope and the recycling of catalyst,it was found that the supported palladium catalyst can effectively catalyze the four-component carbonylative addition reaction of aryl iodides,alkynes,amines and CO,yielding a variety of enaminones in moderate to excellent yield.The hetero-geneous catalyst can be recycled up to 8 times with almost consistent activity.The preparation of enaminones by this method has attractive advantages of mild reaction conditions,high efficiency,good selectivity,simple raw materials and easy operation.The possible mechanism for the heterogeneous palladium-catalyzed carbonylative addition reaction has been proposed.?6?The carbonylative cross-coupling reaction of aryl iodides with arylboronic acids catalyzed by a magnetic nanoparticles-supported bidentate phosphine palladium?II?complex[Fe₃O₄@SiO₂-2P-PdCl₂]with HCOOH as CO source and DCC as activator has been investigated.By optimizing the reaction conditions,it was found that the carbonylative cross-coupling reaction of aryl iodides with arylboronic acids under carbon monoxide gas-free conditions proceeds smoothly in toluene at 100oC,using 3 mol%of Fe₃O₄@SiO₂-2P-PdCl₂ as catalyst and potassium carbonate as base.A wide variety of biaryl ketones have been obtained in moderate to high yield.The new heterogeneous palladium catalyst can be easily separated from the product by simply applying a magnet.The recovered palladium catalyst can be recycled at least10 times without significant loss of activity,which providing a novel and practical method for the synthesis of various biaryl ketones.?7?The carbonylative cyclization of 2-aminobenzonitriles with aryl iodides catalyzed by an MCM-41-supported bidentate phosphine palladium?II?complex[MCM-41-2P-Pd?OAc?₂]has been studied.By optimizing the reaction conditions,it was found that the carbonylative cyclization reaction proceeds smoothly in DMSO/H₂O at 110oC under 10 bar of carbon monoxide by using[MCM-41-2P-Pd?OAc?₂]as catalyst and K₂CO₃ as base.A wide range of 2-aryl-substituted quinazolinones have been synthesized in good yield,which providing another convenient and practical method for the synthesis of quinazolinone derivatives.