2-硅萘与甲醛及二苯甲酮环加成反应的理论研究

采用密度泛函理论(DFT)方法在B3LYP/6-311G**水平研究了2-硅萘与甲醛和二苯甲酮的[2+2]和[4+2]杂环加成反应的微观机理、势能剖面,考察取代基和苯溶剂对反应势能剖面的影响.计算结果表明,所研究反应均以协同但非同步的方式进行.羰基C原子上的苯取代基不利于反应的进行,而2-硅萘分子中Si原子上的C(CH3)3,CCl3及NH2取代基均有利于反应的进行.苯溶剂对所研究反应的势能剖面影响不大.[2+2]反应比相应的[4+2]反应容易进行,此结果与实验一致.

通过RAFT聚合和点击反应合成苯乙烯和丙烯酸丁酯的多嵌段共聚物

通过可逆加成断裂链转移(RAFT)聚合和Cu催化炔基-叠氮环加成反应(CuAAC),合成出了苯乙烯(St)和丙烯酸丁酯(BA)的多嵌段共聚物。首先用双炔基三硫代碳酸酯S,S′-双(α,α′-二甲基?α″-炔丙基乙酸酯基)三硫代酸酯(BPTTC)作为RAFT试剂,进行苯乙烯的聚合。然后丙烯酸丁酯和苯乙烯嵌段共聚,得到聚(苯乙烯-b-丙烯酸丁酯-b-苯乙烯)三嵌段共聚物。最后,三嵌段共聚物和等物质的量的1,5-二叠氮戊烷反应得到(ABA)n型多嵌段共聚物。聚合物通过1 H NMR和GPC测试方法表征。根据偶联反应前后的聚合物数均相对分子质量计算,平均重复嵌段的数量DPn可达到27。

铜粉催化氰化物与NaN_3的环加成反应研究

文章研究了普通铜粉催化体系催化氰化物与NaN_3的[2+3]环加成反应。研究结果表明,以铜粉作为催化剂,Et_3N作为助催化剂,DMF/MeOH(9∶1)为溶剂,将氰化物与NaN_3于常压、温度为55~60℃下反应12 h,合成5-取代四唑化合物,其收率可达85%左右。该方法具有催化剂廉价易得且用量少、反应条件温和、耗时少、产率高、后处理操作简单等优点。

苯炔与二炔的[2＋2＋2]环加成反应制备菲类衍生物

菲及菲类衍生物广泛应用于合成树脂、染料、农药和植物生长激素等领域。在无催化剂存在的条件下,利用苯炔的高反应活性,通过苯炔和偶联二炔获得了具有炔基功能基团的二取代的菲类化合物,产率为76%~83%。利用核磁共振和高分辨质谱等手段对所得化合物进行了结构解析：所得化合物是通过2个苯炔分子和1个二炔分子上的叁键间的[2＋2＋2]环加成反应实现的;二炔分子中残留的1个叁键可进一步功能化,制备其他菲类衍生物。

SYNTHESIS AND CHARACTERIZATION OF TRIAZOLE CONTAINING LIQUID CRYSTALLINE POLYMERS THROUGH 1,3-DIPOLAR CYCLOADDITION POLYMERIZATION

Liquid crystalline polymers containing 1,2,3-triazole units as linking groups have been synthesized from the monomers containing triad ester diazide and flexible dialkyne ester by 1,3-cycloaddition reaction and were characterized. Click reaction of azide and alkyne functionals catalyzed by Cu(I) yielded target polyesters with 1,2,3-triazole groups.The structure of the polymer was confirmed by spectral techniques.GPC analysis reveals that the polymers have moderate molecular weight with narrow distribution.H...

铑催化的环丙烷类化合物的环化反应研究进展

环丙烷已被有机化学家们广泛的应用于构筑多元碳环以及多元杂环的合成中,通常采用的是过渡金属或者过渡金属衍生的配体作为催化剂。文章选取铑催化剂,阐述其在环丙烷的环化反应中的研究进展。

Microwave-assisted Synthesis of New 1,2,3-Triazoles Bearing an Isoxazole Ring by the Azide-alkyne Cycloaddition Click Chemistry

A comparison synthesis of 1,2,3-triazoles bearing isoxazole ether was developed between conventional and microwave-assisted heating. Single/donble 1,2,3-triazoles bearing isoxazole ether were synthesized by click reaction starting from substituted isoxazolyl alkyne compounds and substituted benzyl azide compounds or neopen- tylglycol diazide in the presence of copper（I） that in-aim generated. Herein, the effect of different catalysts on the yield was researched by conventional method, and the optimal catalyst was selected. The structures of all the synthe- sized compounds were confirmed by MS, FTIR, ^1H and ^13C NMR spectroscopies. Moreover, the crystal structure of 5-{[（1-benzyl-1H-1,2,3-triazol-4-yl）methoxvlmethvl}-3-（4-fluoroohenvl）isoxazole（2h） was determined.

Water-soluble Cu30 nanoclusters as a click chemistry catalyst for living cell labeling via azide-alkyne cycloaddition

Cu(I)-catalyzed azide-alkyne cycloadditions(CuAAC)have gained increasing interest in the selective labeling of living cells and organisms with biomolecules.However,their application is constrained either by the high cytotoxicity of Cu(I)ions or the low activity of CuAAC in the internal space of living cells.This paper reports the design of a novel Cu-based nanocatalyst,watersoluble thiolated Cu30 nanoclusters(NCs),for living cell labeling via CuAAC.The Cu30 NCs offer good biocompatibility,excellent stability,and scalable synthesis(e.g.,gram scale),which would facilitate potential commercial applications.By combining the highly localized Cu(I)active species on the NC surface and good structural stability,the Cu30 NCs exhibit superior catalytic activities for a series of Huisgen cycloaddition reactions with good recyclability.More importantly,the biocompatibility of the Cu30 NCs enables them to be a good catalyst for CuAAC,whereby the challenging labeling of living cells can be achieved via CuAAC on the cell membrane.This study sheds light on the facile synthesis of atomically precise Cu NCs,as well as the design of novel Cu NCs-based nanocatalysts for CuAAC in intracellular bioorthogonal applications.

An air-stable supported Cu(?) catalyst for azide-alkyne click polymerization

An air-stable supported Cu(I) catalyst, Cu I@PS-Phen, was designed and synthesized. Cu I@PS-Phen can efficiently catalyze the click polymerization of diynes a and diazides b to produce soluble and thermally stable polytriazoles with high molecular weights(Mw up to 30800), and low copper residue content(down to 190 ppm) in high yields(up to 94.2%) under mild reaction conditions without the exclusion of oxygen.

Tadpole-shaped polymers based on UV-induced strain promoted azide-alkyne cycloaddition reaction

In the present study, we synthesized well-defined tadpole-shaped polystyrene(PS) via the combination of atom transfer radical polymerization(ATRP) and UV-induced strain promoted azide-alkyne cycloaddtion(SPAAC) reaction. A di-bromo ATRP initiator(Br-ini-Br) containing cyclopropenone-masked dibenzocyclooctyne group was used to prepare the linear PS with a cyclopropenone-masked dibenzocyclooctyne in the middle of the chain and bromo groups at both ends(Br-PS-Br). Then we used the single electron transfer-nitroxide radical coupling(SET-NRC) reaction to transfer the bromo end groups to azide groups(N_3-PS-N_3). After UV irradiation, the dibenzocyclooctyne group was quantitatively released, and intramolecularly reacted with alternative azide end group to produce the tadpole-shaped PS based on SPAAC reaction.

Postsynthetic Modification of Metal-Organic Frameworks through Click Chemistry

The postsynthetic modification （PSM） of metal-organic frameworks （MOFs） has emerged as a powerful tool to chemically tailor the interior of MOFs. In this review, we summarize the research progress of PSM of MOFs through click chemistry, including azide-alkyne click reaction and thiol-ene reaction.

Recent Advances of CuAAC Click Reaction in Building Cyclic Polymer

Cyclic polymers have attracted more and more attentions in recent years because of their unique topological structures and characteristic properties in both solution and bulk state. There are relatively few reports on cyclic polymers, partly because of the more demanding synthetic procedures. In recent years, 'click' reaction, especially Cu(I)-catalyzed azide-alkyne cycloaddition(CuAAC), has been widely utilized in the synthesis of cyclic polymer materials because of its high efficiency and low susceptibility to side reactions. In this review, we will focus on three aspects:(1) Constructions of monocyclic polymer using CuAAC 'click' chemistry;(2) Formation of complex cyclic polymer topologies through CuAAC reactions;(3) Using CuAAC 'click' reaction in the precise synthesis of molecularly defined macrocycles. We believe that the CuAAC click reaction is playing an important role in the design and synthesis of functional cyclic polymers.

A one-pot protocol for copper-mediated azide–alkyne cycloaddition using alkenyl triflate precursors

On the basis of the mild transformation of alkenyl triflates into alkynes promoted by LiCl, a one-pot protocol using alkenyl triflate precursors was developed for copper-mediated azide–alkyne cycloaddition. This protocol may provide an opportunity of sequentially click reactions for the construction of bifunctional probes in chemical biology studies.

Cu2O nanocrystals with various morphology:Synthesis,characterization and catalytic properties

Cu2O nanocubes,octahedra,spheres and truncated rhombic dodecahedral were prepared and their structural,morphological,and electronic properties were investigated by X-ray diffraction analysis.X-ray absorption near edge structure,scanning electron microscope and transmission electron microscope and X-ray absorption near edge structure.Cu2O nanocrystals were successfully employed to catalyze the 1,3-dipolar cycloaddition reaction for the synthesis of 1,4-disubstituted triazoles.Cu2O nanocubes and octahedral showed the superior catalytic performance in the cycloaddition reaction.These results reveal that crystal-plane engineering of oxide catalysts is a useful strategy for developing efficient catalysts for organic reaction.