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次磷酸及其盐类在催化剂的作用下,可以还原碳碳双键,碳碳三键,碳氮双键,碳氮三键和碳氧双键.次磷酸盐为氢源的氢转移反应经济安全无污染,它还原有机化合物的反应及产物结构也独特之处.本文对次磷酸盐作为氢源在碳碳双键还原上的应用做了一些综述. 相似文献
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烯烃的亲电加成是有机化学教学的重点及难点内容.本文主要以(Z)或(E)-3-甲基己-3-烯与各类常见的亲电试剂反应为例,详细分析了亲电试剂的结构特征及相应的反应机理,系统地阐述了反应的区域选择性情况及立体化学情况.有助于学生从根本上理解烯烃亲电加成反应实质,从而突破学习的难点问题. 相似文献
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本文通过对乙烯和乙炔的化学键构成、键能的比较 ,以及对乙烯和乙炔与卤化氢和卤素的亲电加成反应中间体物质的分析 ,说明乙烯的亲电加成反应活性大于乙炔的亲电加成反应活性。 相似文献
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羰基化合物是一类极为重要的有机化合物,本文从(1)醛酮(2)环酮(3)α,β-不饱和羰基化合物的结构讨论了羰基结构对其亲核加成活性的影响。 相似文献
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镍金属催化的还原偶联反应可直接利用来源广泛、价格低廉的亲电试剂作为偶联底物,具有反应条件温和、能允许反应中存在少量水和空气、官能团兼容性好等优点。含有季碳结构的化合物广泛存在于多种药物和生物活性的分子中。叔烷基亲电试剂由于空间位阻大、反应活性低、在反应中容易生成其他副产物,作为底物参与还原偶联反应仍具挑战。综述了近十年关于叔烷基亲电试剂作为底物参与的碳碳键还原偶联反应研究进展,讨论了不同催化反应中底物范围及机理。 相似文献
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具有C3对称性的三甲基三嗪(TMT)分别与2,4,6-三(4-醛基苯基)-1,3,5-三嗪(TFPT)、均三苯甲醛(TFB)和四氟对苯二甲醛(TFBA)在酸或者碱催化条件下发生Aldol缩合反应,成功构建出3种新型的碳碳双键桥联的共价有机框架材料(TMT-TFPT-COF、TMT-TFB-COF、TMT-TFBA-COF)。本研究通过Material Studio、ZEO++等软件对材料进行结构的精确解析,并结合粉末X射线衍射(PXRD)、傅里叶红外光谱(FTIR)等表征手段确定了材料的结构、连接方式及其荧光特性。结果表明,这3种较高结晶度的新型共价有机框架材料均为二维层层堆积结构,其中碱催化条件下合成的TMT-TFPT-COF、TMT-TFB-COF材料呈现出良好的荧光性质,此类荧光COFs材料在光催化、化学传感器等方面具有很好的应用潜力。 相似文献
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《国际聚合物材料杂志》2012,61(3-4):435-449
Abstract Based on a kinetic model involving competing parallel reactions for free-radical addition to the double bond of a molecule with the formation of 1:1 adduct and participation of three radical types in the chain propagation, versions of the rate equation with 1 - 3 measurable parameters are derived. These versions make it possible to describe the nonmonotonic (with maximum) dependence of the formation rate of an addition product on concentration of the unsaturated compound. The unbranched chain process occurs in binary liquid systems comprising saturated and unsaturated components at comparable concentrations. Application of the competition kinetics of free-radical addition to oxidation of some hydrocarbons is discussed when the reaction that competes with chain propagation reactions involving the alkylperoxy radical RO2 gives the cyclic alkylhydrotetraoxy radical [R(?H)O4H] as a less reactive radical inhibiting the chain process of formation of the main products of oxidation. 相似文献
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Characterization of Heronamide Biosynthesis Reveals a Tailoring Hydroxylase and Indicates Migrated Double Bonds 下载免费PDF全文
Dr. Yiguang Zhu Dr. Wenjun Zhang Yaolong Chen Dr. Chengshan Yuan Haibo Zhang Dr. Guangtao Zhang Liang Ma Dr. Qingbo Zhang Dr. Xinpeng Tian Prof. Dr. Si Zhang Prof. Dr. Changsheng Zhang 《Chembiochem : a European journal of chemical biology》2015,16(14):2086-2093
Heronamides belong to a growing family of β‐amino acid polyketide macrolactams (βPMs) with an unsaturated side chain. The biosynthetic gene cluster for heronamide F was identified from the deep‐sea‐derived Streptomyces sp. SCSIO 03032. The involvement of the gene cluster in heronamide biosynthesis was confirmed by the functional characterization of the P450 enzyme HerO as an 8‐hydroxylase for tailoring heronamide biosynthesis. The presence of migrated double bonds in the conjugated diene‐containing side chain of heronamides was confirmed by feeding experiments with labeled small carboxylic acid molecules. This study is the first demonstration of migrated double bonds in βPMs with an unsaturated side chain. 相似文献
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Marine C. R. Rauch Yann Gallou Léna Delorme Dr. Caroline E. Paul Prof. Dr. Isabel W. C. E. Arends Prof. Dr. Frank Hollmann 《Chembiochem : a European journal of chemical biology》2020,21(8):1112-1115
Elemental metals are shown to be suitable sacrificial electron donors to drive the stereoselective reduction of conjugated C=C double bonds using Old Yellow Enzymes as catalysts. Both direct electron transfer from the metal to the enzyme as well as mediated electron transfer is feasible, although the latter excels by higher reaction rates. The general applicability of this new chemoenzymatic reduction method is demonstrated, and current limitations are outlined. 相似文献
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