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 …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Ru-, Rh-, and Pd-Catalyzed C-C Bond Formation Involving C-H Activation and Addition on Unsaturated Substrates: Reactions and Mechanistic Aspects

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.

Cobalt-Catalyzed C―H Activation

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.

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

1.

In a sodium peroxydisulfate-sodium cyanide system, the aminyl radicals RCH2CH2NH generated from n-alky1amines undergo N-cyanation to form alkylureas, and are oxidized to aldimines, predecessors of N-alkyl alkanamides and 2,5,6-trialkyl-1,3-diox-4-enes.




2.

The introduction of sodium hydroxide to the oxidizing system favors the increase in the yield of alkylureas and alkyl cyanamides to 70%. 2-(Alkylamino)alkanonitriles are also formed. A simple method for separating the reaction products has been developed.




3.

In the oxidation of sec-alkylamine, cyclohexylamine, oxidative deprotonation predominates over the N-cyanation reaction.

Oxidative cyanation of aminyl radicals in sodium peroxydisulfate-sodium cyanide system

1

The radical-chain process for the formation of γ-lactones from alcohols andβ-alkyl-substitutedα, β-unsaturated acids is accelerated substantially with increase in the pressure




2

Sterically hindered reactions, which practically do not go under ordinary conditions, can be run at a pressure of 10,000 kgf/cm2 to give γ-lactones in a preparative yield

Free-radical addition of alcohols to α, β- unsaturated acids under high pressure

Conformational Analysis of 2,3-Disubstituted 1,4-Dithianes (I) and (II) by NMR Spectroscopy and MMX Calculations.

Synthesis of Peroxide Compounds by the BF3-Catalyzed Reaction of Acetals and Enol Ethers with H2O2.

As a result of photolysis of aromatic bromo- and chlorohydrocarbons in benzene solution, products of replacement of the halogen atoms by a phenyl group were obtained.

G. I. Nikishin

Papers

Oxidative cyanation of aminyl radicals in sodium peroxydisulfate-sodium cyanide system

Free-radical addition of alcohols to α, β- unsaturated acids under high pressure

Conformational Analysis of 2,3-Disubstituted 1,4-Dithianes (I) and (II) by NMR Spectroscopy and MMX Calculations.

Synthesis of Peroxide Compounds by the BF3-Catalyzed Reaction of Acetals and Enol Ethers with H2O2.

Photolysis of aryl bromides and aryl chlorides in benzene