Study On The Preparation Of Cu (Pd)/mOF And Their Applications In C-X Bond Formation

Organic compounds containing C-X（X=C,N,O）bonds are widely present in natural products,medicines,pesticides,organic synthesis intermediates,and optoelectronic materials.Therefore,how to efficiently construct C-X bonds is one of the hot spots in organic synthesis research.In recent years,thanks to the discovery of various types of organic ligands,copper-catalyzed Ullmann reactions and palladium-catalyzed Buchwald-Hartwig reactions have been widely studied and applied,and they have played an important role in the synthesis of many functional compounds.However,there are some disadvantages in the homogeneous catalytic system used,such as the difficulty of separating the catalytic system from the product,the inability to recycle the catalytic system,and the pollution of metal residues,which limit its application in some fields.Therefore,in the context of sustainable development and green chemistry concepts,it is of great theoretical and practical significance to develop heterogeneous catalysts to resolve the problem of catalyst separation and recycling.Metal Organic Frameworks（MOFs）,also known as Porous Coordination Polymers（PCPs）,are composed of secondary building units inorganic nodes（metal ions/cluster）and coordination multidentate organic ligands two-dimensional or three-dimensional porous crystalline material formed by the connection.Because of its clear active site and tunable backbone structure,it is often used as a heterogeneous catalyst for a wide variety of organic transformations.However,the reports that copper（palladium）metal is immobilized on MOFs and used to catalyze the formation of C-C and C-N bonds are still extremely limited.In the first part:MOF-253 was prepared from AlCl₃·6H₂O and pyridine dicarboxylic acid as raw materials.Subsequently,MOF-253·Pd（OAc）₂ and MOF-253·CuI were prepared through the dipping method respectively.The structure was characterized by XRD,EA,ICP-OES,IR,etc.,and the metal Pd and Cu content in the structure were determined.Meanwhille,it was used as a heterogeneous catalyst for Sonogashira cross-coupling reaction of aryl iodide/bromo/chloride and terminal alkyne:firstly,the coupling reaction of p-iodoanisole and phenylacetylene was used as a model reaction,and a series of condition optimizations was performed to obtain the optimal reaction conditions:MOF-253·Pd（OAc）₂（0.036 mol%）and MOF-253·CuI（0.397 mol%）as catalysts,K₂CO₃（2.0 equiv.）as base,and reacted at70°C for 12 hours in DMSO（2.0 ml）to obtain a 98%yield.Under the optimal conditions,46 coupling products of aryl iodide/bromide/chloride and terminal alkynes with different substituents were expanded,and the yield was between 45-99%.The catalytic system can also be applied to the simpler synthesis of more complex drug-like molecules,the ethinyl estradiol,ethinyl estradiol,and norgestrel all show good yields（68%-96%）.In this catalytic system,the amount of Pd used was only 0.036 mol%,and the TON value can reach 2722.The catalyst can be reused at least 5 times without significantly reducing its activity.The results of hot filtration test,Hg（0）and PVP poisoning experiments show that the MOF-253 anchored Cu（Pd）/MOF-253 catalyst are an efficient green heterogeneous catalyst in this reaction.In the second part:Used the products of the first part-disubstituted acetylene as substrates,the formation the indole ring through cyclization reaction of substituted 2-iodoaniline with MOF-253·Pd（OAc）₂ as catalysis was studied.Firstly,N-toluenesulfonyl-2-iodoaniline and diphenylacetylene were used as model substrates to optimize the conditions.The optimal reaction conditions were:0.066 mol%MOF-MOF-253·Pd（OAc）₂ as the catalyst and NaHCO₃（5.0 equiv.）as base,DMF（2.0 mL）as solvent,and reaction at 120°C for 24 hours,the yield of model reaction can reach 93%;secondly,using the optimal conditions of the Chapter 1 as the reaction conditions,6 disubstituted diphenylacetylenes were prepared and synthesized.Disubstituted diphenylacetylenes were further explored for substrate applicability,and 27 corresponding target products were synthesized with yields ranging from41%to 93%.Finally,the recycling of the catalyst was carried out.The results showed that the catalyst could be circulated at least three times without significantly reducing the activity.The results of the hot filtration test and the PVP poisoning experiment showed that the Pd-MOF-253 catalyst anchored by MOF-253 reacted here Medium is a highly efficient green heterogeneous catalyst.In summary,two MOF-253·Pd（OAc）₂ and MOF-253·CuI catalysts were prepared and successfully used in the Sonogashira coupling reaction and the indole synthesis reaction.The two systems have used low Pd loading,wide substrate adaptability,and high catalytic efficiency,providing another powerful synthetic method for the formation of C-C and C-N bonds under heterogeneous conditions.