铑(Ⅱ)催化重氮苄基膦酸酯与芳香亚胺的氮杂环丙烷化反应

铑(Ⅱ)催化重氮苄基膦酸酯与芳香亚胺反应,一步合成氮杂环丙烷-2-膦酸酯．该方法立体定向地得到唯一的反式构型产物,反应历程是重氮化合物先与亚胺形成叶立德中间体,然后发生自身环丙烷化反应．     

重氮膦酸酯研究进展

重氮化合物是一类重要的卡宾前体,在有机合成中应用广泛。重氮膦酸酯是含磷重氮化合物,与重氮羧酸酯相比,重氮膦酸酯具有一些特殊的反应类型和反应性质。由于重氮膦酸酯具有丰富的化学转化形式以及含磷功能化合物潜在的生物和药物活性,近年来其合成方法以及反应性质成为化学家们的研究热点。本文综述了近年来重氮膦酸酯的研究和应用进展。     

高立体选择性合成环氧乙烷-2-膦酸酯的研究

利用铑(Ⅱ)催化重氮苄基膦酸酯与芳香醛或酮化学专一地进行环氧化反应,高产率、高立体选择性地合成了顺式环氧乙烷-2-膦酸酯.反应历程是重氮化合物先与醛或酮形成羰基叶立德中间体,然后发生自身环化反应.产物经红外光谱、1H核磁共振谱、质谱和X射线衍射确定结构.     

α-重氮膦酸酯作为亲核试剂参与不对称反应的研究进展

重氮化合物作为一类重要的合成子,在有机合成、药物化学、材料化学及化学生物学等领域均有广泛应用。α-重氮膦酸酯作为α-重氮羧酸酯的电子等排物,可作为亲核试剂参与不对称反应。综述了α-重氮膦酸酯作为亲核试剂参与不对称反应（Mannich反应,Morita Baylis-Hillman反应,类Aldol反应以及［3+2］反应）的研究进展,并对其未来发展进行了展望。     

α-重氮膦酸酯研究进展

重氮化合物作为一类重要的卡宾前体,可以在过渡金属催化下发生X—H(X=C,N,O,S,Si等)插入反应、1,2-氢迁移反应、环丙烷化反应等一系列化学转换,为构建各种药物分子、天然产物以及生物活性分子提供了有效的手段.α-重氮膦酸酯作为一类重要的重氮化合物,同样可以通过化学转化构建各种含磷功能化合物.由于有机磷化合物具有广泛的生物和药物活性,所以研究α-重氮膦酸酯的合成及相关反应性质具有重要的意义,综述了近年来α-重氮膦酸酯的研究进展和应用.     

通过Michaelis-Arbuzov重排合成新型

α-溴代-叔丁基甲基酮和3-取代2,2-二甲基环丙烷羧基氯化物与亚磷酸酯反应,生成膦酸酯,并描述了膦酸酯的溴化反应.     

金催化炔基膦酸酯水合反应合成β-羰基膦酸酯

β-羰基膦酸酯是一类重要的有机化合物和反应中间体,在有机合成及药物化学中发挥着重要的作用.提供了一种高原子经济性、高选择性、温和的炔基膦酸酯水合反应体系.实验结果表明:在阳离子金催化剂(2.5 mol%)的催化作用下,以1,2-二氯乙烷(1 m L)为溶剂,室温下炔基膦酸酯(1 mmol)与水(3 mmol)发生水合反应,高收率、高区域选择性地得到β-羰基膦酸酯化合物(收率≥92%).该方法具有底物适用范围广、反应条件温和、环境友好等优点,为含β-羰基膦酸酯结构单元的天然产物及复杂药物分子的合成提供了一种新途径.     

光化学条件下(β-重氮-α,α-二氟乙基)膦酸酯与羧酸的酯化反应

利用可见光促进的O-H插入反应可以在温和条件下实现羧酸与原位生成的(β-重氮-α,α-二氟乙基)膦酸酯的酯化反应, 以良好的产率得到了含有α,α-二氟甲基膦酸酯的羧酸酯类化合物. 该反应操作简单, 对于不同的官能团具有良好的适应性. 因此, 这一反应为α,α-二氟甲基膦酸酯衍生物的合成提供了一种高效的策略.     

有机催化吲哚与环状酮亚胺膦酸酯的傅-克反应合成含手性季碳胺基膦酸衍生物

在有机合成中,季碳中心的构建始终是一项充满挑战的课题.含手性季碳中心的胺基膦酸化合物以其多样的生物活性,如酶抑制剂、抗真菌剂、抗菌剂和抗病毒剂等,受到了科研工作者的广泛关注.目前已有许多合成策略报道,其中亲核试剂与α-酮亚胺膦酸酯的不对称加成策略为含手性季碳中心胺基膦酸衍生物的合成提供了一条简洁有效的路径,但是却鲜有报道,已有的报道也仅局限于乙酰氰、丙酮、硝基甲烷和芳基硼酸作亲核试剂.为满足多样的手性胺基膦酸衍生物的合成需求,新的合成策略和亲核源仍有待进一步发展.值得一提的是,不对称傅-克反应是一种非常有效的构建碳-碳键的合成方法,并已有广泛报道.基于吲哚与亚胺底物的傅-克反应经验,我们研究组发展了一种有机催化吲哚与环状酮亚胺膦酸酯傅-克反应合成含手性季碳胺基膦酸衍生物的方法,使用的有机催化剂是手性磷酸.通过对溶剂、催化剂和温度的筛选发现,使用在3,3′-位引入吸电子的3,5-二三氟甲基苯基取代的H8-BINOL衍生的手性磷酸作催化剂,反应温度为30 oC,溶剂为均三甲苯时,最高能以98%对映选择性得到含手性季碳胺基膦酸酯化合物.该反应操作简单,条件温和,不仅适用于吲哚衍生物,对吡咯也能取得较好结果.总之,该方法提供了一条简洁有效的合成手性胺基膦酸衍生物的途径.     

硝基烷基膦酸酯碳负离子烷基化反应区域选择性研究

α-或β-硝基烷基膦酸酯双负离子与卤代烷反应, 生成碳-烷基化产物, 反应区域选择性取决于硝基膦酸酯的结构, 讨论了可能的反应机理。     

Highly efficient synthesis of linear pyrrole oligomers by twofold Heck reactions

The twofold Heck reaction of the vinylpyrroles 3a and 3b with the iodobenzenes 4a-c led to the linear pyrrole oligomers 5, 6, and 7. The synthesis of both symmetrical and unsymmetrical oligomers, such as 10a and 10b, was also accomplished by a Heck reaction of 8 and 9 and by a Heck reaction of 3a and 11 followed by a Wittig reaction and a second Heck reaction with 8. The pentacyclic oligomers 14 and 19 were prepared by a twofold Heck reaction of 13 with 4 and by a twofold Heck reaction of 15 with 16 followed by a Wittig reaction and a twofold Heck reaction with 8.     

HCN + OH→CN + H2O反应理论研究

The reaction path of the reaction HCN + OH→ CN + H2O was traced with Fukui's theory of intrinsic reaction coordinate by using ab initio MO method (at UMP4/6-31G** level) with gradient technique. On this basis, the dynamics properties along the reaction path was investigated by reaction path Hamiltonian theory. The rate constants of this reaction at different temperatures were calculated by conventional and variational transition state theory with tunneling correction. The theoretically calculated rate constants are in good agreement with experimental results, this shows that the title reaction is an one step, direct reaction.     

HCN OH─→CN H_2O反应理论研究

HCN是硝胶推进剂热分解的一种主要产物，了解它与OH的反应机理对理解这些推进剂的作用原理有极大的帮助问．Miller和Bowman认为HCN被OH氧化是碳氢化合物火焰中含氮燃料转化为NOx的重要途径问．实验上，W0oldridge、Hanson和Bowman等人研究了HCN＋OH～CN＋HOH的反应，得到了该反     

Molecular transformations of unsaturated thiacrown ethers

Unsaturated thiacrown ethers with 15, 18, and 21 members were oxidized to sulfoxides by the reaction with m-CPBA. The reaction with t-BuOCl at -20 degrees C also afforded sulfoxides, whereas the reaction at room temperature yielded cis-trans isomerized compounds. The cis-trans isomerized compound was also obtained by the photochemical reaction or by the reaction with NCS and NCP. Meanwhile, the reaction with NBS and NBP provided an acetal via 1,2-bridged bromonium intermediate.     

HNCO+OH->H2O+NCO的反应机理

采用从头算分子轨道法 (UHF/6 31G 水平 ,并用MP4加以相关能校正 )研究了HNCO OHH2 O NCO反应机理 .同时用Morokuma数值法获得了反应途径即内禀反应坐标 (IRC) .沿着IRC ,运用反应途径哈密顿理论 ,获得反应途径动态学信息 .在此基础上 ,根据过渡态理论和相应隧道效应校正 ,计算了在不同温度下的反应速率常数 ,得到了和实验相一致的结果 .计算结果表明 ,此反应是一步直接型的抽提H反应 .     

焦炭溶损反应动力学及其模型研究

利用未反应核收缩模型对高炉焦炭与CO2的反应动力学进行了研究，建立了以可测参数（R）表达的焦炭与CO2的反应动力学关系式。并对反应速率常数和有效扩散系数、表观反应活化能和有效扩散活化能及反应过程中各步骤阻力进行了分析。结果表明，（1）焦炭与CO2的反应符合未反应核收缩模型。（2）反应的表观活化能Ea=124.5kJ/mol，有效扩散活化能ED=642.4 kJ/mol；界面化学反应的阻力随反应温度升高而增加；残余灰层内的内扩散传质阻力相对比例随温度升高而下降。（3）焦炭溶损反应在低温区主要受内扩散控制，随着温度升高，反应由外扩散、化学反应和内扩散三步控制；当进入高温区，反应进行一段时间后主要受内扩散控制。     

Study of the reaction between 1,5-naphtalene diisocyanate and polycaprolactone in different solvents

The reaction between polycaprolactone and 1,5-naphtalene diisocyanate has been investigated in solvents with different dielectric constants and hydrogen bonding powers (toluene, ethyl acetate, ethyl methyl ketone), and in the same solvents with the addition of a catalytic amount of dimethyl sulfoxide (DMSO). The reaction was considered to proceed over two steps, the reaction of the first NCO group being faster. The course of the reaction was measured by titration of the unreacted NCO groups, ¹H- and ¹³C-NMR spectroscopy, and size exclusion chromatography. By titration only the overall reaction order and reaction rate constants could be determined. DMSO accelerated the reaction in all three solvents, which was explained by the stabilization of the activation complex by DMSO. Both steps of the reaction could be specified by NMR spectroscopy. The ratio between the reaction rate constants for the first and the second step decreased with the increased hydrogen bonding strength of the solvent and with DMSO. By SEC only the reaction of the first NCO group could be determined due to the low resolution for higher molar mass reaction products with a broad distribution. The values obtained for the first step reaction rate constants were in good agreement with NMR values. © 1995 John Wiley & Sons, Inc.     

The photokinetics of phenothiazine dyes with titanium trichloride in different solvents

The kinetic parameters of photoinduced electron transfer reaction of two phenothiazine dyes, methylene blue and methylene green with titanium trichloride, were determined in water and different aqueous-alcoholic solvents at different acidities by using a specially designed optical system. The rate of photoinduced electron transfer reaction was measured by determining the quantum yield of the reaction. The methylene green had a higher reactivity as compared to methylene blue with titanium trichloride. The graphical analysis showed that the reaction of dye with titanium trichloride follows pseudo–first-order kinetics. A reaction mechanism was proposed by considering the different excited states of dye and their possible interaction with the solvent and titanium trichloride. The different steps in the reaction mechanism were taken into consideration for deriving rate equations, which were used to determine the different rate constants in the reaction mechanism in different solvents.     

The photo-dehydro-Diels-Alder (PDDA) reaction

The photo-dehydro-Diels-Alder (PDDA) reaction is a valuable extension of the classical Diels-Alder (DA) reaction. The PDDA reaction differs from the DA reaction by the replacement of one of the C-C-double bonds of the diene moiety by a C-C triple bond and by the photochemical triggering of the reaction. This entails that, in contrast to the DA reaction, the PDDA reaction proceeds according to a multistage mechanism with biradicals and cycloallenes as intermediates. The PDDA reaction provides access to a considerable variety of compound classes. For example, 1-phenylnaphthlenes, 1,1'-binaphthyls, N-heterocyclic biaryls, and naphthalenophanes could be obtained by this reaction.     

金属卟啉催化环己烷羟基化反应中环己酮的形成机理研究

单金属卟啉和双金属卟啉催化下PhIO常温氧化环己烷的羟基化反应中金属卟啉结构和反应溶剂、反应温度、反应时间等环境因素对产物酮含量及酮形成反应动力学的影响进行了系统研究, 并与金属卟啉催化下PhIO氧化环己醇的反应进行了对比, 提出了金属卟啉催化下环己烷羟基化反应中产物酮的形成机理。