Alder-ene reaction of aryne with olefins

A novel intermolecular Alder-ene reaction based on aryne and olefins was developed. We performed this transformation under mild conditions such as at room temperature, and this reaction displayed high selectivity and good yields only in the presence of CsF. Hence, the intermolecular Alder-ene reaction of aryne with olefins provides an effective route to synthesize derivatives of olefins.     

The reaction of the trichloromethylium ion with olefins

The reactions of [CCl₃]⁺ with ethylene, 1-hexene, cyclopentence, cyclohexene and styrene have been studied in a field-free, high-pressure ion source by time-resolved ion collection following a short ionizing pulse of electrons. Ethylene is completely unreactive, while addition of [CCl₃]⁺ to the olefinic bond of the other compounds is followed by loss of one or more HCl molecules to give unsaturated cations. Only styrene forms a stable adduct [MCCl₃]⁺ which is an arenium ion produced by addition to the aromatic ring. Rate constants for the reaction of [CCl₃]⁺ have been determined and show that whereas reaction with styrene occurs at almost every ion-molecule collision, with 1-hexene and cyclopentene only 15% of the collisions lead to reaction.     

Photochemically induced coupling reaction of triarylstibines with olefins

Photoreaction of triarylstibines with styrenes resulted in the formation of 2-aryl-1-phenylethanols accompanied by air oxidation. Formation of the products has been explained by the valence expansion of the oxygen-antimony-styrene complex to a five-valent intermediate, followed by reductive coupling.     

A new mechanism for the reaction of ozone with olefins

A mechanism for ozone–olefin reactions is developed that is consistent with the recent findings of several investigations. These findings suggest a reaction sequence leading to the production of fewer free radical species than has been assumed in the past. Computer simulations using the new mechanism reproduce experimental results obtained from the ozonolysis of propylene in air.     

New epoxidation of olefins with superoxide anion in the presence of organic sulfur compounds

Epoxidation of olefins such as stilbene and chalcone with superoxide anion in the presence of several sulfur compounds was investigated.     

Palladium-catalyzed reaction of bromine- and iodine-containing isothiazoles with olefins

3-Bromo-4-alkenylisothiazoles were synthesized by the reaction of 3-bromo-4-iodoisothiazole with olefins in the presence of palladium acetate Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 534–536, March, 1998.     

New data on the free radical reaction of alcohols with olefins

Conclusions The radical reaction of alcohols with alkenes-1 proceeds at both carbon atoms of the double bond. As a result, a mixture of the two 1 1 adducts, consisting chiefly of the addition products of the alcohol at the CH₂ group, with a small content (4–13%) of the addition product at the CH group, is formed.     

Kinetics and mechanism of the reactions of the superoxide ion in solutions. III. Kinetics and mechanism of the reaction of the superoxide ion with ethyl acetate in dimethylformamide,acetonitrile, and their mixtures

The kinetics of the reaction of the superoxide ion with ethyl acetate have been studied in DMF, AN, and their mixtures. It was shown that the rate constants depend on the ethyl acetate concentration, which indicates the formation of an intermediate in this process. Equilibrium constants for the process of the intermediate formation and the rate constants for its decay have been determined. It is concluded that aprotic solvents affect mainly the stage of the intermediate decay in this reaction.     

Palladium-catalyzed Heck-type reaction of 2-chloro acetamides with olefins

Conditions have been developed for the palladium-catalyzed Heck-type reaction of 2-chloro acetamides with several olefins. The regiochemistry of the products obtained speaks in favor of an involvement of palladium enolates in this reaction.     

全氟烷基磺酰溴与杂原子取代烯键的反应

全氟烷基磺酰溴与杂原子取代烯烃, 如溴乙烯, 乙酸乙烯酯, 三甲基硅乙烯加成, 得相应的加成物, 与烯醇硅醚反应, 水解后得到α位溴代酮和全氟烷基亚磺酸. 全氟磺酰氯与1-三甲基硅氧基-1-叔丁基乙烯在紫外光照下反应, 生成α位全氟烷基化的酮. 全氟烷基磺酰溴溴化苯酚和甲氧基苯, 得到对位溴化产物. α,α-二氯三氟乙基亚磺酸钠与溴水在20-25℃反应, 得α,α-二氯三氟乙基磺酰溴, 其化学反应性与全氟烷基磺酰溴类似, 但稳定性较差.     

On the reaction of superoxide ion with organochloric compounds

Superoxide ions were generated by the action of γ-radiation on water-alcohol solutions saturated with oxygen. The reaction of superoxide ions with sodium 2,4-dichlorophenoxyacetate and pentachlorophenol was studied. The reaction of O₂ ^?? with chloroaromatic compounds results in elimination of chloride ions and formation of phenyl radicals active in elimination of hydrogen atoms. The rate constant of the reaction between O₂ ^?? and 2,4-dichlorophenoxyacetate was calculated using the method of mathematical simulation.     

Kinetics of the reaction of cyclopentane with trichloroethylene

The kinetics of the thermally and radiation initiated chain reaction between trichloroethylene and cyclopentane to produce 1,1-dichlorovinylcyclopentane and hydrogen chloride have been investigated in the temperature range 250–360°C at high pressure in the gas phase. The rate governing step in the chain is (k₃ = 3.3 × 10⁹ exp ?(4800/RT) cc mole^?1 sec ^?1). The rate of the unimolecular decomposition of trichloroethylene is 1.4 × 10¹⁴ exp ?(61,200/RT) sec^?1.     

Kinetics of the reaction of OH with HCl

The rate constant of the reaction OH + HCl → H₂O + Cl was measured in a flow tube over the temperature range 224 to 460°K using resonance fluorescence detection of OH. An Arrhenius expression k₁ = (2.0 ± 0.1) × 10^?12 exp [?(620 ± 20 cal/mole)/RT] was obtained. Stratospheric and reaction kinetic implications are discussed briefly.     

Kinetics and mechanism of the doping-addition of Arscl to olefins

A lithium percholate effect on the rate and product ratio of 2,4-dinitrobenzenesulfenyl chloride doping-addition to 1-methylcyclopropene (5) and tetrafluorobenzobarrelene (10) in acetic acid has been examined. The rates of both doping-addition reactions follow the normal salt effect dependence. However, the yields of doping-addition products is much higher than expected from the term k_o.b.[LiClO₄] at low concentrations of the salt added and, hence, the catalytic influence of LiClO₄ on product formation is much more pronounced than expected from normal salt effect dependence. The mechanism of doping-addition is analyzed in detail.     

Tributylstannyl radical-catalyzed reaction of 1,2,3-selenadiazoles with olefins or dienes

It was found that the reaction of 1,2,3-selenadiazoles derived from cyclic ketones with olefins or dienes was markedly promoted by a catalytic amount of tributylstannyl radical, which was generated in situ from tributylstannyl hydride or allyltributylstannane and AIBN, to give the corresponding dihydroselenophenes in moderate to good yields. In contrast, when 1,2,3-selenadiazoles prepared from linear and aromatic ketones were used as substrates, the same reaction did not take place, and alkynes were formed as the sole product.