Reaction of trialkylsilanes with phenol in the presence of metal halides

Summary We studied the reaction of phenol with trialkylsilanes of various structures, catalyzed by metal halides. The most suitable halides for this reaction are those of Cr, Co, Ni, Ge, Zn, Sn, and Hg. The reaction rate depends on the structure of the trialkylsilane and the amount and nature of the metal halides.The reaction of trialkylsilanes with phenol, catalyzed by metal halides, is a simple and convenient method of synthesizing trialkylphenoxysilanes, which are formed in yields of up to 98% of theoretical.We synthesized 16 trialkylphenoxysilanes (13 of which were prepared for the first time) and determined their properties. 16 trialkylsilanes were prepared as starting materials and 8 of these were described for the first time.     

The Kharasch type reaction of allylic halides with Grignard reagent in the presence of transition metal halides

The reaction of allylic halide with Grignard reagent in the presence of transition metal chloride has been investigated. Three reactions of allylic halide occurred competitively; (i) reduction to olefin, (ii) coupling with Grignard reagent to olefin (cross-coupling) and (iii) coupling with itself to 1,5-diene (homo-coupling). The relative importance of these reactions depends on both the structures of allylic halide and Grignard reagent, as well as on the transition metal salt utilized. The mechanism was discussed in terms of the allylic transition metal intermediate.     

Kinetic study of wood pyrolysis in presence of metal halides

The purpose of this work was to study the kinetics of wood pyrolysis in the presence of inorganic salts, representatives of classes of alkali and alkaline earth metal halides (NaCl, KCl, KBr, CaCl₂, BaCl₂·2H₂O) and Lewis acids (AlCl₃·6H₂O, FeCl₃·6H₂O, CuCl₂, CuBr₂, ZnCl₂·1.5H₂O, NiCl₂·6H₂O, SnCl₂·2H₂O) using TG-DSC. The activity of these catalysts was estimated by the temperature of the beginning of pyrolysis, charcoal yield and kinetic parameters, such as energy of activation and reaction order. Using the Lewis acids as catalysts for pyrolysis leads to a decrease in the temperature of the process beginning and the activation energy. In the presence of other catalysts activation energy does not significantly change. The increase of a seeming reaction order in the presence of Lewis acids possibly is a consequence of complication of the thermodestruction mechanism, with the appearance of new parallel competing stages.      

Reaction of pentahalo-substituted pyridines with potassium halides in presence of 18-crown 6-ester

Conclusions The formation of 2,4,6-trifluoro-3,5-dichloropyridine by the reaction of pentachloropyridine with KF in MeCN, in the presence of catalytic amounts of an 18-crown 6-ester, proceeds at considerably lower temperatures and is not complicated by the presence of the reverse reaction.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 949–950, April, 1978.     

Evidence for the intermediacy of π-allylic metal complexes in the reaction of allylic halides with grignard reagent in the presence of transition metal halides

The reactions of allyl bromide and crotyl chloride with Grignard reagent catalyzed by π-allyl and crotyl metal complexes of nickel, cobalt, and iron, and the stoichiometric reaction of the complexes with the Grignard reagent have been examined. The similarity in catalytic behaviour of the complex and the corresponding metallic halide affords further evidence in support of the previous proposal that the π-allylic metal intermediate plays an important role in the catalytic reaction. The stoichiometric reaction suggests that the dependence of distribution of product in the catalytic process on the type of both allylic halide and metal is attributable to the facility of ligand exchange between the π-allylic complex and Grignard reagent.     

Reaction of methyl hypochlorite with certain olefins in the presence of boron trifluoride

Fluoro chlorides are major products in the reaction of methyl hypochlorite with certain olefins in the presence of boron trifluoride.     

Reaction of methyl trichloroacetate with vinyltrimethylsilane in the presence of metal carbonyls

Reaction of methyl trichloroacetate with vinyltrimethylsilane initiated by metal carbonyls yields, depending on the crbonyl, methyl-2,2,4-trichloro-4trimethyl-silyl butyrate [with Mn₂(CO)₁₀ or Re₂(CO)₁₀], 2,2-dichloro-4-trimethylsilyl--butyrolactone [with Fe(CO)₅ or Mo(CO)₆], or a mixture of adduct and lactone [with Cr(CO)₆ or W(CO)₆]. Prior nucleophilic addition of potassium acetate to metal carbonyls of Fe, Mo, Cr, and W suppresses lactonization and an adduct is formed. In the case of Fe(CO)₅, HMPA, DMF, and PPh₃ react analogously.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2615–2618, November, 1989.     

Reaction of 2,4,6-tri-tert-butylphenoxyl with oxygen in the presence of metal compounds

Conclusions A dependence was found for the isomer composition of the quinolide peroxides formed upon the oxidation of 2,4,6-tri-tert-butylphenol on the coordination capacity of the metal compounds used for the oxidation and the medium. Kinetic measurements showed that the reaction of 2,4,6-tri-tert-butylphenoxyl with oxygen is accelerated in the presence of manganese diacetate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 706–709, March, 1986.     

Reaction of N-vinylimidazoles with alkyl halides

Quaternary salts of N-vinylimidazole and N-vinylbenzimidazole were synthesized. The structures of the products of quaternization of the N-vinylimidazoles were proved by IR and UV spectra. The distribution of the -electron density in the N-vinylimidazole molecules was obtained by quantum-chemical calculation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 958–960, July, 1971.     

Reaction of dialkyldithiotrimethylsilylphosphites with acyl halides

It has been established that S,S-dialkyltrimethylsilyldithiophosphites react with acyl halides in two directions, depending on the nature of the halogen in the acyl halide and on the reaction conditions, thus giving as the main reaction products either dialkyldithiohalophosphites or dialkyldithioacylphosphonates. The latter compounds react with acyl halides in accordance with a retro-Arbuzov reaction scheme, giving dialkyldithiohalophosphites.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, Kazan 420083. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 1011–1016, April, 1992.