- Solvent-induced dichotomy in the oxidation mechanism of alkyl aromatic selenoethers
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Changing solvent polarity (considered in terms of dielectric permittivity ? is an easy experimental way for tuning the reactivity of electrogenerated cation radicals of alkyl aromatic selenoethers. First-order cleavage of SeC3 bond is favored in polar media, whereas bimolecular cation radical disproportionation becomes the main reaction in low-polar solvents. The key element of this dichotomy is the dielectric adjustment of specific transannular interactions between Se and CO group in the cation radicals. A series of alkyl arylselenides with pending carboxy or acetamido substituents was studied by cyclic voltammetry, IR spectroscopy and DFT calculation in binary solvents covering the span of polarity 8 2Se 2.
- Fechete, Ioana,Jouikov, Viatcheslav
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p. 634 - 640
(2014/07/21)
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- Stereoelectronic effects in the reactivity of electrogenerated cation radicals of arylselenides
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The role of stereoelectronic effects in the electrochemical oxidation of arylselenides Se-substituted by a trimethylsilylmethyl group and those with substituents bearing a carbonyl group have been considered. Although the HOMO of these compounds is formed of pz-type electrons of the ArSe moiety, the predominant contribution from the lone pair of Se makes the heteroatom more susceptible to direct electronic effects than to effects transmitted through the aromatic ring. The σ-p hyperconjugation and the interaction through space were shown to lower the charge localization on the reaction center and to stabilize cation radicals of these compounds, thus changing the control of the potential-determining reaction and promoting second order reactions.
- Jouikov,Fattakhova
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p. 220 - 230
(2007/10/03)
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- Oxidative Cleavage of Diselenide by m-Nitrobenzenesulfonyl Peroxide. Novel Method for the Electrophilic Benzeneselenenylations of Olefins and Aromatic Rings
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Diphenyl diselenide was found to be readily converted into benzeneselenenyl-m-nitrobenzenesulfonate (PhSeOSO2C6H4NO2-m) by treating with m-nitrobenzenesulfonyl peroxide.When the selenenyl sulfonate thus formed was allowed to react in situ with olefins, such as cyclohexene, 1-octene, or styrene, in the presence of various nucleophiles, the adducts of benzeneselenenyl group and a nucleophile were obtained.As the nucleophiles water, methanol, acetic acid, phenol, and anisole could be employed; oxyselenenylated : R=H, Me, Ac, and Ph) and arylselenenylated : R=H and Me) adducts were afforded.Phenol gave oxyselenenylated products in cyclohexene or 1-octene and arylselenenylated products in styrene.Efficient intramolecular cyclizations of unsaturated alcohols and carboxylic acids were similarly performed by the selenenyl sulfonate to afford corresponding benzeneselenenylated cyclic ethers and lactones.The selenenyl sulfonate was also found to be a highly reactive benzeneselenenylating reagent for aromatic rings, such as anisole, phenol, acetanilide, toluene, and benzene.
- Yoshida, Masato,Sasage, Shuichi,Kawamura, Kyoko,Suzuki, Takashi,Kamigata, Nobumasa
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p. 416 - 422
(2007/10/02)
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- Synthetic Approach to the Amphilectane Diterpenes: The Use of Nitriles as Terminators of Carbocation-Olefin Cyclizations
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A biomimetic approach to the synthesis of tricyclic terpenoid isonitriles from marine sponges is described which involves carbocation-olefin cyclization of polyolefinic precursors terminated by the stereoselective formation of a carbon-nitrogen bond.The k
- Stevens, Robert V.,Albizati, Kim F.
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p. 632 - 640
(2007/10/02)
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- Simple Procedure for the Aminoselenation of Olefins
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The reaction of phenylselenenyl chloride with olefins in acetonitrile in the presence of an acid catalyst and water is a convenient method for the aminoselenation of olefins.
- Toshimitsu, Akio,Aoai, Toshiaki,Uemura, Sakae,Okano, Masaya
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p. 1041 - 1042
(2007/10/02)
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