Vasily N. Korotchenko

A novel approach to fluoro-containing alkenes

A new and general one-pot transformation of aromatic aldehydes to fluorinated olefins containing –CHC(Cl)CF3 or –CHC(F)CClF2 moieties is described. Freons CCl3CF3 and CCl2FCClF2 were used as trifluoromethyl and difluoromethyl C2-building blocks respectively. A proposed mechanism for the reaction is discussed.

A Novel Synthetic Approach to Dichlorostyrenes

Abstract We found that N -unsubstituted hydrazones of aromatic aldehydes can be easily converted to the corresponding 1,1-dichlorostyrenes in the reaction with carbon tetrachloride using copper (I) chloride as catalyst. Factors affecting the route of the reaction and yields of the products were investigated. A proposed mechanism for the reaction is discussed.

A novel direct synthesis of (2,2-difluorovinyl)benzenes from aromatic aldehydes

A novel catalytic approach to (2,2-difluorovinyl)benzenes has been developed. It was found that hydrazones of aromatic aldehydes generated in situ could be converted to the corresponding (2,2-difluorovinyl)benzenes by catalytic olefination reaction (COR) with dibromodifluoromethane in the presence of CuCl.

Novel efficient synthesis of dibromoalkenes. A first example of catalytic olefination of aliphatic carbonyl compounds

A new simple and efficient one pot transformation of various aliphatic carbonyl compounds to the corresponding dibromoalkenes is described. A wide range of hydrazones of aldehydes and ketones, prepared in situ, were easily converted into dibromoalkenes by treatment with carbon tetrabromide in the presence of CuCl. The reaction proceeds under mild conditions to give the target products in good to high yields.

Catalytic olefination of carbonyl compounds. A new versatile method for the synthesis of alkenes

The review is devoted to a new catalytic olefination reaction (COR) discovered by the authors. This is the reaction between N-unsubstituted hydrazones of carbonyl compounds with dihalides CHal2XY in the presence of copper(i) chloride to give substituted alkenes. Catalytic olefination is versatile. Variation of the carbonyl and olefinating components opens up the way for the synthesis of various classes of unsaturated compounds including those containing functional groups. The reaction mechanism is discussed and a catalytic cycle describing the process is proposed. A model for estimating and predicting the reactivity of halogen-containing compounds in the COR is developed. The relationship between the structure of the carbonyl substrates and their behavior in the title reaction is elucidated.

New method for the synthesis of β-bromostyrenes

A new stereoselective method was developed for the synthesis of β-bromostyrenes (E/Z > 5/1) starting from hydrazones of aromatic aldehydes and bromoform in the presence of CuCl.

A novel reaction of double carbon-carbon bond formation: synthesis of 2,2-dichlorostyrenes

Currently, metal complex catalysis is one of the most intensely developing fields of organic chemistry. Great at tention is devoted to the oxidation of a wide range o f organic compounds by oxygen in the presence of copper-conta ining systems, i However, examples of using other oxidants in the presence of copper compounds are rather rare. 2 Polyhaloalkanes (most often, carbon tetrachloride) can act as such oxidants. 3-8 We found a novel redox reaction of double carboncarbon bond formation catalyzed by copper salts, which permits the preparat ion of 2,2-dichlorostyrenes from N-unsubstituted hydrazones of aromatic aldehydes.

Reaction of catalytic olefination of hydrazones with polyhaloalkanes. Investigation of alkene formation chemoselectivity

Hydrazones of carbonyl compounds at treatment with polyhaloalkanes in the presence of CuCl as catalyst are converted into substituted alkenes with formation of a new C=C bond.

New Synthesis of β-Iodostyrenes

A general procedure for the synthesis of β-iodostyrenes is proposed. Aromatic aldehyde and ketone hydrazones are converted into the corresponding β-iodostyrenes by treatment with CHI3 in the presence of a catalytic amount of CuCl.

Catalytic olefination reaction of carbonyl compounds. A study on stereoselectivity of alkene formation

The mechanism of formation of alkene stereoisomers in the catalytic olefination reaction of carbonyl compounds was studied. 4-Chlorobenzaldehyde hydrazone 1 stereoselectively reacts with a number of F-, Cl-, Br-, and I-containing polyhaloalkanes in the presence of catalytic amounts of CuCl to give ω-substituted styrenes 2 with the more thermodynamically stable alkene isomer being the major product. A model for the formation of the stereoisomers of alkenes 2 in the olefination reaction is proposed. Stereoselectivity of the reaction is determined by elimination of copper(ii) halides from the lowest-lying conformers of organocopper intermediates II. According to quantum-chemical calculations, the elimination should involve the staggered conformations with antiperiplanar arrangement of C—Hal and C—Cu bonds and proceed by the E2 anti-elimination mechanism. The results of quantum-chemical calculations are in good agreement with the experimental E/Z alkene isomer ratios.