Application Of Acid Siloalumina-zeolite In Catalytic Construction Of C-C And C-O Bonds

The construction of C-X（X=F,Cl,C,O,S,etc.）bond is the most direct and effective way to synthesize multiple functional molecules.In particular,it has been an important branch of synthetic chemistry because the C-O bond can be directly synthesized into ethers,ketones and some chiral alcohols.Among them,asymmetric ethers and ketones are widely used in the synthesis and development of antidepressant drugs and advanced degradable materials due to their medicinal value and degradation properties.In addition,the construction of C-C bond is a time-honoured field,and a variety of effective strategies have been widely applied to the construction of C-C bonds of C_sp3-C_sp3,C_sp3-C_sp2,C_sp2-C_sp,C_sp2-C_sp2and C_sp2-C_sp.However,it is difficult to selectively construct C_sp-C_spbond due to the structural rigidity of≡C-H impeded rotation.Therefore,in this paper,acidic silicon-alumina-zeolite Beta was used as heterogeneous catalyst to construct C=O bonds,C-O bonds and C_sp-C_spbonds.The first part:Carbonyl compounds（C=O bond）were successfully prepared by hydration of alkynes using zeolite Beta as catalyst.The system avoids the use of metal catalysts,organic ligands and mineral acids,and uses water as a solvent to avoid the use of organic solvents.Beta catalyzed hydration of alkynes to construct C=O bonds showed high catalytic activity,substrate range and good functional group compatibility.Ideal product yields（>96%）were obtained for alkynes with different substituents at 120 ^oC for 6 hours.The second part:The preparation of asymmetric ethers,also known as aromatic acetals,by alcohol-aldehydes condensation reaction,is an important reaction for the construction of C-O bond.In most of these reactions,mineral acids and metal oxides are needed as catalysts,which not only complicate the reaction system but also corrode the equipment.Therefore,we tried to use Beta as a catalyst to study the reaction paths of alcohol-aldehyde condensation catalyzed by heterogeneous solid acid in detail.The third part:Alkyne coupling is the most commonly used method to construct the C_sp-C_spbond.Cu（II）salts are usually required as catalysts to construct C_sp-C_spbonds by alkyne coupling in the presence of amino ligands.Because the activation and coupling of alkynes are two separate processes that occur at different active centers,the reaction often requires two or more steps,reducing the reactivity.In this paper,supported Cu-NH₄⁺heterogeneous catalyst（Cu-NH₄⁺/Beta）was prepared by modifying Cu Ox anchored on Beta with inorganic amine.The catalyst showed high catalytic activity in the reaction of C_sp-C_spbond catalyzed by alkyne coupling.