Addition of primaryN-nitroamides to activated olefins

PrimaryN-nitrosulfamides readily undergo addition to acrolein and vinyl ketones to yieldN--oxoalkyl-N-nitrosulfamides. The presence of a second substituent at the double bond hinders the reaction.N-Nitrourethane reacts with activated carbonyl compounds and -nitroolefins.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1261–1263, July, 1994.     

Addition of hydrogen halides to fluoro olefins

Summary Addition of hydrogen halides to perfluoropropylene and perfluoroisobutylene was accomplished and a series of compounds prepared.     

Addition of sulfur radicals to fullerenes

The addition of oxygen‐centered radicals to fullerenes has been intensively studied due to their role in cell protection against against hydrogen peroxide induced oxidative damage. However, the analogous reaction of sulfur‐centered radicals has been largely overlooked. Herein, we investigate the addition of S‐centered radicals to C₅₀, C₆₀, C₇₀, and C₁₀₀ fullerenes by means of DFT calculations. The radicals assayed were: S, SH, SCH₃, SCH₂CH₃, SC₆H₅, SCH₂C₆H₅, and the open‐disulfide SCH₂CH₂CH₂CH₂S. Sulfur, the most reactive species, prefers to be attached to a 66‐bond of C₆₀ with a binding energy (E_bind) of 2.4 eV. For the SR radicals the electronic binding energies to C₆₀ are 0.77, 0.74, 0.58, 0.67, and 0.35 eV for SH, SCH₃, SCH₂CH₃, SCH₂C₆H₅, and SC₆H₅, respectively. The reactivity of C₆₀ toward SR radicals can be increased by lithium doping. For Li@C₆₀, the E_bind is increased by 0.65 eV with respect to C₆₀, but only by 0.33 eV for the exohedral doping. Fullerenes act like free radical sponges. Indeed, the C₆₀‐SR E_bind can be duplicated if two radicals are added in ortho or para positions. The enhanced reactivity because of multiple additions is mostly a local effect, although the addition of one radical makes the whole cage more reactive. Therefore, as observed for hydroxylated fullerenes, they should protect cells from oxidative damage. However, the thiolated fullerenes have one advantage, they can be easily attached to gold nanoparticles. For the addition on pentagon junctions smaller fullerenes like C₅₀ are more reactive than C₆₀. Interestingly, C₇₀ is as reactive as C₆₀, even for the addition on the equatorial belt. For larger fullerenes like C₁₀₀, reactivity decreases for the carbon atoms belonging to hexagon junctions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Addition of trichloromethyl radicals to tetrachloroethylene

The gamma-radiation-induced free-radical chain reactions in liquid CCl₄? C₂Cl₄? c? C₆H₁₂ mixtures were studied in the temperature range of 363–448°K. The main products in this system are chloroform, hexachloropropene and chlorocyclohexane. These products are formed via reactions (1)–(5): with G values (molec/100 eV) of the order of magnitude of 10² and 10³ at the lowest and highest temperatures, respectively. Values of k₂/k₁ were determined from the product distribution. In turn, these values gave the following Arrhenius expression for k₂/k₁ (θ = 2.303RT, in kcal/mol): From this result and the previously determined Arrhenius parameters of reaction (1), k₂ is found to be given by .     

Addition of S-benzoyl phenylselenosulfide to olefins: selenothiocarboxylation

Heating of S-benzoyl phenylselenosulfide and olefins with AIBN afforded selenothiocarboxylated products generated by a free radical process with high regiospecificity but lack of stereoselectivity.     

Reaction of methoxy radicals with oxygen. I. Using dimethyl peroxide as a thermal source of methoxy radicals

Using dimethyl peroxide as a thermal source of methoxy radicals overthe temperature range of 110–160°C, and the combination of methoxy radicals and nitrogen dioxide as a reference reaction: a value was determined of the rate constant for the reaction of methoxy radicals with oxygen: is independent of nitrogen dioxide or oxygen concentration and added inert gas (carbon tetrafluoride). No heterogeneous effects were detected. The value of k₄ is given by the expression In terms of atmospheric chemistry, this corresponds to a value of 10^5.6 M^?1·sec^?1 at 298 K. Extrapolation to temperatures where the combustion of organic compounds has been studied (813 K) produces a value of 10^7.7 M^?1·sec^?1 for k₄. Under these conditions, reaction (4) competes with hydrogen abstraction or disproportionation reactions of the methoxy radical and its decomposition (3): In particular k₃ is in the falloff region under these conditions. It is concluded that reaction (4) takes place as the result of a bimolecular collision process rather than via the formation of a cyclic complex.     

Reactions of fluoro olefins Communication 18. Addition of acid phosphono- and phosphoro-thioic esters to perfluoro olefins

Russian Chemical Bulletin -     

Determination of absolute rate constants of addition of ethyl radicals to olefins

Theoretical and Experimental Chemistry -     

Concept of polarity of free radicals in reactions of addition to olefins

The concept of polarity (nucleo- and electrophilicity) of free radicals in processes of addition to unsaturated substrates was developed within the framework of the method of qualitative potential energy surfaces on the basis of an analysis of the interaction of diabatic surfaces for reactions of free-radical addition to olefins. A formulation is given for the concept of the polarity (philicity) of the attacking free radical; the theoretical index of philicity and the criterion of polarity of the radicals are proposed; the concept of ambiphilicity of a radical is introduced. The chemical aspects of the philicity of free radicals — the influence of a change in it on the formation and height of the activation barrier of the reaction and the strength of the bond formed — are discussed. A parallel formulation of the concept of polarity of radicals in terms of boundary orbital interactions in the free-radical-unsaturated substrate system is given.Translated from Teoreticheskaya i Éxperimental'naya Khimiya, Vol. 22, No. 5, pp. 562–571, September–October, 1986.     

Preparative trapping of tert-butoxy radicals by captodative olefins

tert-Butoxy radicals generated either thermally or photochemically are trapped preparatively by various captodative olefins.     

Addition of radicals to quinones—II. ESR spectra of radicals derived from fluoranil

In systems consisting of thermally decomposing benzoyl peroxide in alkylbenzenes, fluoranil behaves as a selective spin trap. As a result of charge transfer (CT) complex formation between alkylbenzenes and fluoranil, the latter traps secondary radicals formed via H-atom abstraction by phenyl radicals from the alkyl group of the aromatic solvents. Weaker CT interaction leads to the trapping of phenyl radicals. The kinetic isotope effect in H-atom abstraction leads to the same result.