Cyclodextrin Assisted Organic Catalytic Reaction

Cyclodextrins(including a-cyclodextrins,?-cyclodextrins and y-cyclodextrins)and their derivatives have important applications in organic catalysis.It is widely used in the fields of oxidation,reduction,cross coupling,addition,photocatalytic isomerization,1,3-dipole cycloaddition,and green chemistry.Our group has carried out a series of studies in the field of cyclodextrin catalyzed organic reactions.On the basis of these work,my doctoral thesis mainly studies the organocatalytic reaction assisted by cyclodextrin.Cyclodextrin and organic inorganic materials are used as catalytic carriers for organic catalysis.The research of composite catalysts composed of cyclodextrin,hyperbranched polyamide amine,inorganic gold nanomaterials and palladium nanoparticles were involved.This paper mainly includes the following parts:1.?-Cyclodextrin Modified Gold Nanoparticles:Catalytic Applica-tions and Molecular SelectivityL-Cys-?-CD@AuNPs nanoparticles were synthesized by a green method of the reduction of HAuCl4 with NaBH4 and L-Cys-CD.The catalytic activity of L-Cys-?-CD@AuNPs nanoparticles in the reactions of 4-nitrophenol and 4-nitro-l-naphthol was researched in detail.Because of the selective binding of?-CDs to different guest molecules,L-Cys-?-CD@AuNPs exhibits diverse catalytic activities for different substrates.The experimental results prove that L-Cys-?-CD@AuNPs shows better catalytic efficiency for the reduction of 4-nitro-l-naphthol than p-nitrophenol.2.One-Pot Multicomponent Synthesis of 2-Amino-4H-benzo[b]pyrans Catalyzed by?-Cyclodextrin Modified Hyper-branched PolymerWe report a ?-cyclodextrin modified catalyst ECD-CD@PAAs was prepared by an simple and effective method.An efficient multicomponent reaction of aromatic aldehyde,1,3-cyclohexanedione/dimedone,and malononitrile was researched by using the synthetic ECD-CD@PAAs.As a supramolecular host for aromatic substrates and an effective catalyst,ECD-CD@PAAs synthetized 2-amino-4H-benzo[b]pyrans and a series of derivatives in expected yields under mild reactions.Further more,this catalyst with excellent functional group tolerance and can be reused and recycled multiple times without apparent loss of its catalytic activity.3.Palladium Nanoparticles Supported on ?-cyclodextrin Func-tionalised Poly(amido amine)s and Its Application in Su-zuki-miyaura Cross-Coupling ReactionHerein,we researched the synthesis,characterization and the catalytic application of organic-inorganic hybrid material Pd@PAAs-CD as an efficient catalyst for the Suzuki-Miyaura coupling reaction under mild reaction conditions.Pd@PAAs-CD was confirmed by FT-IR,TEM,SEM,ICP-AES and NMR analyses.Futhermore,we have developed an efficient protocol by using Pd@PAAs-CD for the catalysis of suzuki-Miyaura cross-coupling reaction in water with high yield.CD as the mediator modified on PAAs advanced the dispersion of palladium nanoparticle(Pd NPs)and promoted the process of catalytic reaction through the host-guest interaction of CD.Meanwhile,the Pd@PAAs-CD could be recycled and reused in cross-coupling reaction.4.Poly(amido amine)s with Different Branched Architecture:Synthesis,Reactivity and Their Application in Gene DeliveryPoly(amido amine)s with diverse topographical structures are promising candidates for gene delivery and drug carriers.This paper reports a series of Poly(amido amine)s with the same repeating units,however,different degree of branching,were successfully prepared by Michael addition polycondensation of N,N-methylenebis(acrylamide)(MBA)and L-cysteine methyl ester hydrochloride(Cys)in a water/dimethyl sulfoxide co-solvent.The experimental results show that different amine/cyclodextrin modified cationic PAAs have good DNA condensation capacities.