A. V. Shastin

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.

New approach to the synthesis of trifluoromethylvinyl sulfides

Nucleophilic substitution reaction of halogen atom in β-chloro-and β-bromo-β-trifluoromethylstyrenes by thiolates was studied. Stereo-and regioselectivity of the reaction with respect to the electronic and sterical properties of substituents in the aromatic ring of starting styrenes was investigated. Regioisomer with geminal trifluoromethyl and alkyl-or arylthio groups was found to be formed predominantly or exclusively. The reaction proceeds stereoselectively in nearly quantitative yields. On this basis, a new convenient stereoselective method for the synthesis of trifluoromethylvinyl sulfides was elaborated.

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.

Synthesis of 5-dinitromethyltetrazole

A convenient method of synthesizing 5-dinitromethyltetrazole on the basis of 1,1-diamino-2,2-dinitroehtilene was developed.

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.

Conversion of aromatic aldehydes into 1-aryl-2,2-dichloroethenes

A new general one-pot preparative method for the synthesis of 1-aryl(hetaryl)-2,2-dichloroethenes from aldehydes was developed. The method involves successive conversions of the latter into hydrazones followed by treatment with carbon tetrachloride in the presence of copper(i) chloride.

Synthesis and thermal decomposition of ditetrazol-5-ylamine

Ditetrazol-5-ylamine (DTA) was synthesized from cyanuric chloride in four steps. The thermal decomposition of DTA in the solid state was studied by thermogravimetry, volumetry, mass spectrometry, IR spectroscopy, and calorimetry. Under isothermal conditions at 200–242 °C, thermal decomposition obeys the first order autocatalytic kinetics. The kinetic and activation parameters of DTA decomposition were determined. The composition of gaseous reaction products and the structure of condensed residue were studied. The thermal effect of thermal DTA decomposition is 281.4 kJ mol−1. The nitrogen content in a mixture of gaseous products formed by the reaction in a temperature interval of 200–242 °C exceeds 97 vol.%.

New method for the synthesis of α-chlorocinnamonitriles

A novel method for the preparation of nitriles of α-chlorocinnamic acid from aldehydes and ketones was proposed. Transformation of carbonyl compounds into hydrazones followed by treatment of the reaction mixture with CCl3CN in the presence of copper chloride(i) yields α-chlorocinnamonitriles.