Catalytic Transformations of Bornyl Chloride under the Action of AlCl3

The composition of products formed in catalytic transformations of bornyl chloride under the action of AlCl₃ was studied.     

Transformations of Cyclic Acetals under the Action of Some Organic and Inorganic Oxidants

Liquid-phase oxidation of cyclic acetals and 2,2-disubstituted 1,3-dioxacyclanes with dimethyldioxirane, Caro salt, potassium persulfate, and complex of potassium chlorodiperoxochromate with 15-crown-5 was studied.     

Transformations of n-Hexane and Cyclohexane by Barrier Discharge Processing in Inert Gases

The conversion of n-hexane and cyclohexane by barrier discharge treatment in He, Ar, Kr, or Xe was studied. The action of a barrier discharge on n-hexane vapor primarily results in the formation of branched-chain hydrocarbons (93.48 wt %). Bicyclohexyl is the main reaction product of cyclohexane; alkyl and alkenyl substituted cyclohexanes (48.12 wt %) are also formed. Using n-hexane as an example, it was demonstrated that the energy consumption increased from 1.30 to 2.17 keV per hydrocarbon molecule converted in the following order of inert gases: He, Ar, Kr, and Xe.     

Mechanically Initiated Reaction of Aluminum with Alkyl Halides

Mechanochemical reactions of aluminum with alkyl halides were examined at room temperature. The reaction was initiated by mechanical activation of vibromilling without any activator. It was found that the initiation was not due to the temperature rise at mechanical contact but the active sources formed on aluminum surface by vibromilling. The reactivity of milled aluminum was well correlated with the intensity of exoelectron emission. Both the reactivity and the emission intensity increased sharply after 60 min of milling. The decaying characteristics by exposure of preactivated aluminum were observed for both the reactivity and the emission intensity. The role of exoelectron on the reaction was discussed.     

Kinetic Regularities of Electrochemical Reduction of Organic Halides under the Action of Cobalt Complexes with 2,2'-Bipyridine

Organic halides undergo electrocatalytic reduction under the action of coordinately unsaturated with respect to 2,2'-bipyridine (bipy) complexes Co^{+ 1}bipy (at the first wave potentials) and coordinately saturated complexes Co^{- 1}bipy₂ ^- (at the second wave potentials). The logarithms of the apparent rate constants logk _{a p p} decrease with increasing difference in the reduction potentials of substrate and catalyst E _p A-RX over a wide range of the motive forces of the process.     

Transformations of xylenes in trimethylammonium hydrochloride—Aluminum chloride ionic liquid

Isomerization of m-, o-and p-xylenes in the presence of trimethylammonium hydrochloride-AlCl₃ ionic liquid with different composition was studied. Ionic liquids with the following ammonium salt: AlCl₃ molar ratios were used: 1∶2, 1∶1.5 and 1∶1.25. It was shown that isomerization of xylenes proceeds under mild conditions at temperatures from 60°C to 110°C. It was found that the activity and selectivity of the ionic liquids depends on their composition. The most effective catalyst was the ionic liquid with the ammonium salt: AlCl₃ molar ratio equal to 1∶2.     

温和条件下环己烷的均相催化氧化

温和条件下环己烷的均相催化氧化吴泽彪，张铭俊，奚祖威（中国科学院大连化学物理研究所，大连１１６０２３）关键词环己烷，氧化，均相催化．１．前言饱和烃的氧化是很多化学家都感兴趣的一个前沿性课题．强共价Ｃ─Ｈ键由于键能大，若进行剧烈氧化则产物选择性较差，氧...     

Complexes of Aluminum and Gallium Halides with Dibutylamine: Structures and Properties

The reactions of dibutylamine (DBA) with aluminum tribromide and gallium trichloride (MX₃) in a benzene solution were studied using calorimetric and dielectrometric titration. The formation of stable and highly polar molecular complexes DBA · M₂X₆, DBA · MX₃, 2DBA · MX₃, and 6DBA · MX₃ was established.     

In Situ Generated Palladium Nanoparticles for Catalytic Dehalogenation of Aryl Halides and Deboronation of Arylboronic acids

Palladium nanoparticles in situ generated from palladacyclic complexes efficiently catalyzed the deboronation of arylboronic acids and the dehalogenation as well as homo‐coupling of aryl iodides in an alcohol medium under basic conditions. Isotope labeled studies indicated that the β‐elimination of alcohols provided the hydrogen source for the reaction.     

Transformations ofmyo-inositol hexa-O-nitrate under the action of amines

Reactions ofmyo-inositiol hexa-O-nitrate with ammonia and primary amines yield tetrahydroxy-1,4-benzoquinone derivatives,viz., its tetraammonium salt and its diimines, respectively. Reactions with secondary and tertiary amines give salts of rhodizonic acid, which are converted into salts of croconic acid under certain conditions. The reactions with secondary amines involve intermediate formation of radical species, which were dectected by ESR spectroscopy. A scheme for the chemical transformations ofmyo-inositol hexa-O-nitrate under the action of amines was proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2962–2967, December, 1996.     

Transformations of 3-formylindoles under the action of acids

Under the influence of acids 3-formylindole forms urorosein (the salt of di(indol-3-yl)methylium) which is unstable in solution and decomposes to give a series of indole derivatives, among which 6-(indol-3-yl)-5H,7H-indolo[2,3-b]carbazole and tri(indol-3-yl)methylium salt predominate. N,N′-Dimethylurorosein in solution also forms a mixture of indole derivatives, from which tri(1-methylindol-3-yl)methylium salt, 5N,11N-dimethylindolo[3,2-b]carbazole and its 6-(1-methylindol-3-yl) derivative were isolated. Research Institute of New Antibiotics, RAMN (Russian Academy of Medical Science), Moscow 119867, Russia; Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 631–639, May, 1999.     

Transformations of diallylsilanes under the action of electrophilic reagents

Reactions of dimethyl-, diphenyl-, and (chloromethyl)methyldiallylsilanes with acetic, trifluoroacetic, triflic acids and complex BF₃ · 2AcОH are studied. Depending on the structure of the starting diallylsilane and the nature of the electrophilic reagent the following processes are realized: addition of an electrophile to one СС bond; expulsion of one or two molecules of propene with addition of the electrophile residue to the silicon atom; and rearrangement with elimination of one allyl group from silicon and its attachment to the second allyl group of diallylsilane. Quantum chemical calculations of all three types of transformations are performed on the example of the reactions of dimethyl- and bis(chloromethyl)diallylsilanes with HF, CF₃COOH, CF₃SO₃H, as well as of the intermediate carbenium and silicenium cations.     

Copper-Catalyzed Addition of Grignard Reagents to in situ Generated Indole-Derived Vinylogous Imines

Chiral indole derivatives are ubiquitous motifs in pharmaceuticals and alkaloids. Herein, the first protocol for catalytic asymmetric conjugate addition of Grignard reagents to various sulfonyl indoles, offering a straightforward approach for the synthesis of chiral 3-sec-alkyl-substituted indoles in high yields and enantiomeric ratios is presented. This methodology makes use of a chiral catalyst based on copper phosphoramidite complexes and in situ formation of vinylogous imine intermediates.     

原位生成的烯丙基磷叶立德与醛的化学反应性研究

介绍了我们小组最近有关原位生成的烯丙基磷叶立德与醛的化学反应性研究结果.在化学计量叔膦作用下,烯丙基碳酸酯或联烯酸酯经原位生成的烯丙基磷叶立德活性中间体,与醛发生高度立体选择性的三组分Wittig烯化反应和vinylogous Wittig烯化反应,该类反应为合成多取代1,3-二烯衍生物提供了简单、高效的新方法;在催化量叔膦作用下,γ-甲基联烯酸酯经烯丙基磷叶立德关键中间体与醛发生多个膦催化的环化反应,为五元、六元含氧杂环化合物的合成提供了原子经济性的方法.通过氘代实验和核磁跟踪等方法,对上述反应机理进行了初步探索.