G. I. Nikishin

Bio: G. I. Nikishin is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Radical & Homolysis. The author has an hindex of 11, co-authored 280 publications receiving 540 citations.

Oxidative decarboxylation of dicarboxylrc acids by lead tetraacetate and oxidation of generated carboxyalkyl radicals by Pb(IV) and Cu(II) carboxylates

Abstract: 1. The reaction of lead tetraacetate with dicarboxylic acids of general formula RCH2CH(COOH)(CH2)n-COOH (R=Alk, n=1, 2, 3 or 10) in the presence of pyridine led to their selective oxidation decarboxylation and the generation of carboxyalkyl radicals RCH2ĊH(CH2)COOH. In a similar manner, the 1-(carbomethoxymethyl)nonyl and 2-carbomethoxycyclohexyl radicals were obtained from the monomethyl esters of the 2-octylsuccinic and cyclohexane-1,2-dicarboxylic acids. 2. The main products when the radicals are oxidized with the Pb(IV) and Cu(II) carboxylates are alkenoic acids and their esters, γ- and δ-laetones (in the oxidation of the carboxylalkyl radicals with n = 2 and 3), and esters of acetoxy-substituted monocarboxylic acids (when oxidation is with Pb(IV) carboxylates). 3. The carboxy and carbomethoxy groups in the 2- and 3-carboxy- and 2-carbomethoxyalkyl radicals direct the oxidativeΒ-deprotonation of these radicals under the influence of copper ions predominantly toward the formation of alkenoic acids or of their esters, where the double bond is further away from the functional group.

Reaction of peroxydiglutaric acid with salts of variable valence metals in aqueous solution

Abstract: 1. The decomposition of peroxydiglutaric acid in aqueous solution under the influence of FeSO4 proceeds by the one-electron transfer mechanism, and makes it possible to selectively generate 3-carboxypropyl radicals. 2. The 3-carboxypropyl radicals that are formed in this system are converted into products by three directions: they are cyclized toγ-butyrolactone, dimerized to suberic acid, and they cleave hydrogen to give butyric acid. 3. Water cannot serve as a hydrogen donor for the 3-carboxypropyl radicals; organic compounds function as the substrate here.

1 H and 31 P NMR study of Rh(I)trimethylphosphine complexes and their adducts with molecular oxygen

Abstract: 1. According to1H and31P NMR spectra, the cationic complexes [Rh(PMe3)4]X (X=Cl, BPh4) exist in solution (H2O, MeOH, MeCN) as fluxional five-coordinate species [Rh(PMe3)4. (solvent)]X. 2. The synthesized complexes [Rh(PMe3)4O2]Cl and [Rh(PMe3)4O2]BPh4 have trigonal bipyramidal structure in solution according to31P and1H NMR spectroscopy.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Cobalt-Catalyzed C―H Activation

Abstract: Catalytic C–H activation has emerged as a powerful tool for sustainable syntheses. In the recent years, notable success was achieved with the development of cobalt-catalyzed C–H functionalizations with either in situ generated or single-component cobalt-complexes under mild reaction conditions. Herein, recent progress in the field of organometallic cobalt-catalyzed C–H activation is reviewed until November 2015.

Catalytic Enantioselective Transformations Involving C-H Bond Cleavage by Transition-Metal Complexes.

Abstract: The development of new methods for the direct functionalization of unactivated C–H bonds is ushering in a paradigm shift in the field of retrosynthetic analysis. In particular, the catalytic enantioselective functionalization of C–H bonds represents a highly atom- and step-economic approach toward the generation of structural complexity. However, as a result of their ubiquity and low reactivity, controlling both the chemo- and stereoselectivity of such processes constitutes a significant challenge. Herein we comprehensively review all asymmetric transition-metal-catalyzed methodologies that are believed to proceed via an inner-sphere-type mechanism, with an emphasis on the nature of stereochemistry generation. Our analysis serves to document the considerable and rapid progress within in the field, while also highlighting limitations of current methods.