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.

Participation of Cu(III) in copper sulfate-catalyzed oxidation of 3-carboxypropyl radicals with S2O8 2− ions

Abstract: A mechanism was proposed for the selective oxidative cyclization of 3-carboxyprqpyl radicals to γ-butyrolactone when using the Na2S2O8-CuSO4 oxidation system. In this mechanism the Cu(III) ions take part in the reaction.

Homolytic oxoalkylation of furan, α-methylfuran, and thiophene

Abstract: 1. Homolytic substitution in the heteroaromatic ring of furan,α-methylfuran, and thiophene by CH3COCH2 and CH3 COCHCOCH3 radicals generated from acetone and acetylacetone using Mn(III) acetate (a one-electron oxidizing agent) proceeds regiospecifically at theα-carbon atom of the ring and leads to 2-furyl- and 2-thienyl ketones. 2. Acetoxylation and C-C or C-O dehydrodimerization occurs in the oxidation of 2-furyl- and 2-thienyl ketones by Mn(III) acetate. The reaction pathway depends on the concentration of Mn(OAc)3.

One-electron oxidation of stilbene with metal salts

Abstract: 1. Oxidation of cis- and trans-stilbene with Mn(III) and Co(III) acetates and Tl(III) trifluoroacetate yielded the corresponding acetates and trifluoroacetates of isomeric hydrobenzoins (meso- and dl-). 2. The stereoisomeric composition of the oxidation products does not depend on concentration of initial olefin. 3. A mechanism was proposed for the process, including intermediate formation of the ion-radical salt:\([stilbene]^{\mathop \cdot \limits^ + } [MX_3 ]^{\mathop \cdot \limits^ - } \).

Electrochemical oxidation of 1,3-diketones in the presence of hydrohalic acid salts

Abstract: In the presence of a mediator (sodium iodide) acetylacetone dimerizes with the formation of 3,4-diacetylhexane-2,5-dione, with a yield up to 90%. Salts of 2-halosubstituted 1,3-diketones form more highly enolized cyclic 1,3-diketones — 1,3-cyclohexanedione and dimedone under analogous conditions, with a yield up to 90%.

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.