Vinylation of 3-pyridazones

The vinylation of 3-pyridazones through a step involving the production of 2-hydroxy-and 2-chloroethyl-substituted compounds with subsequent dehydrochlorination, as well as vinylation by means of vinyl acetate, in all cases leads only to N-vinyl derivatives. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 394–397, March, 1980.     

Gas-Phase Vinylation of N-Methylacetamide

Catalysts for selective gas-phase vinylation of N-methylacetamide with acetylene were studied. These catalysts were obtained by applying to wide-pore silica gel of the CdO-K₂O-ZnO system or applying to commercial Al₂O₃ of the CdO-K₂O and CdO-K₂O-ZnO systems.     

Vinylation of pyridylcarboxamides with vinyltrimethoxysilane

A convenient method has been developed for the direct N-vinylation of pyridylcarboxamides with vinyltrimethoxysilane in the presence of copper(II) acetate and tetrabutylammonium fluoride. The yield of N-vinylamides depends on the nature of the starting amide and the solvent. The molecular structure of the products was confirmed by X-ray structural analysis.     

Vinylation of imidazole and benzimidazole

The reaction of imidazole and benzimidazole with acetylene under pressure in the presence of caustic potash has been studied. The corresponding N-vinyl derivatives have been obtained with yields of 80–86%.     

Vinylation of pyrroles in dimethyl sulfoxide

A number of 1-vinylpyrroles were obtained in up to 97% yields by base-catalyzed addition of substituted pyrroles to acetylene in dimethyl sulfoxide at 80–100°C.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 213–214, February, 1977.     

Vinylation of alcohols by 10-vinylphenothiazine

Conclusions The mechanism of vinylation of alcohols by 10-vinylphenothiazine in the presence of organic-electron acceptors was investigated. The main vinylating species was the vinyl cation, the decay product of the 10-vinylphenothiazine radical cation.DeceasedTranslated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2108–2110, September, 1985.     

Cobalt-Catalyzed Vinylation of Organozinc Reagents with Aldehydes

Transtion metal catalyzed vinylation of organic halides are known to be a very convenient method for forming carbon-carbon bonds at unsubstituted vinylic position. The versatility of stilbenes is well known because of its various biological active components, the variety of its reactions in organic syntheses, and its ability to function as a bonding partner for metals in complexes. Many methods have been described for the synthesis of stilbenes. The reduction, dehydrogenation, and elimination reactions leading to stilbenes without formation of new carbon-carbon bonds are known to be a very convenient methods. Synthetically more important are the dimerization reactions: oxidative or eleminative dimerization of a suitable methylarene often constitutes the method of choice for the preparation of a symmetric stilbene. Meerwein arylation and Heck reaction are prominent examples for the synthesis of stilbenes from arenes and styrenes. Moreover, condensation reactions of a nucleophilic with an electrophilic arylmethyl compound include Knoevenagel type reactions and the very general Wittig and Wittig-Horner reactions are also known methods.     

Vinylation of Unprotected Phenols Using a Biocatalytic System

Readily available substituted phenols were coupled with pyruvate in buffer solution under atmospheric conditions to afford the corresponding para‐vinylphenol derivatives while releasing only one molecule of CO₂ and water as the by‐products. This transformation was achieved by designing a biocatalytic system that combines three biocatalytic steps, namely the C? C coupling of phenol and pyruvate in the presence of ammonia, which leads to the corresponding tyrosine derivative, followed by deamination and decarboxylation. The biocatalytic transformation proceeded with high regioselectivity and afforded exclusively the desired para products. This method thus represents an environmentally friendly approach for the direct vinylation of readily available 2‐, 3‐, or 2,3‐disubstituted phenols on preparative scale (0.5 mmol) that provides vinylphenols in high yields (65–83 %).     

Complexes of lanthanides with triethanolamine

Reactions of equimolar amounts of Cp₃Er or amides [(Me₃Si)₂N]₃Ln (Ln = Y, Nd) with triethanolamine lead to the formation of insoluble products of the composition Ln(OC₂H₄)₃N. Naphthalene complex of Eu(II), Cl₁₀H₈Eu(THF)₃, reacts with triethanolamine also with the formation of insoluble compound of trivalent europium Eu(OC₂H₄)₃N. Erbium aminoalkoxide Er(OC₂H₄)₃N actively reacts with carbon dioxide at room temperature and atmospheric pressure in THF to form the adduct Er[OC(O)OC₂H₄]₃N. In the reaction of triethanolamine with the excess of [(Me₃Si)₂N]₃Ln (Ln = Y, Eu) in THF soluble binuclear complexes of the composition [(Ne₃Si]₂NLn(OC₂H₄)₃NC₂H₄OLn[N(SiMe₃)₂]₂(THF) are formed. The reaction of triethanolamine with [(Me₃Si)₂N]₃Y in 3:1 ratio in THF gives the compound Y[OC₂H₄N(C₂H₄OH)₂]₃. The composition and structure of obtained complexes was established by elemental analysis and the IR and NMR spectroscopy.     

Vinylation of tetralin in the presence of peroxide

Summary In the presence of di-tert-butyl peroxide, acetylene adds to the saturated ring in tetralin.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 351–353, February, 1965     

Vinylation of Alkyl Halides Catalyzed by Palladium Catalyst

The palladium catalyzed vinylation of alkyl halides, especially benzyl chlorides, with a variety of olefins has been studied. A possible free radical mechanism was proposed.     

Vinylation of aryl bromides using an inexpensive vinylpolysiloxane

[reaction: see text] A mild and general method for the palladium-catalyzed vinylation of aryl bromides has been developed. The use of tetrabutylammonium fluoride (TBAF) as the activator and an inexpensive and nontoxic vinyl donor, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D(4)(V), 1), allows for a general and high-yielding preparation of substituted styrenes.     

Vinylation of hydroxy-containing cyclic formaldehyde acetals with acetylene

Nucleophilic addition of alcohols having cyclic acetal fragments to acetylene smoothly occurs under relatively mild conditions (KOH, 100–125°C, 1–2 h, initial acetylene pressure 11–12 atm) to give the corresponding vinyl ethers in 80–83% yield.     

铜催化含氮和硫化物的乙烯基化反应研究

以铜为催化剂,结合不同的反应条件,分别阐述了酰胺、胺、唑类化合物和硫化物与卤代烯烃的交叉偶联反应,从而分别得到了各种烯酰胺、烯胺、N-烯基唑类化合物和烯基硫醚化合物.上述亲核试剂与1,4-二卤-1,3-二烯化合物反应,经过两次乙烯基化反应,可以高效地得到各种取代的吡咯和噻吩衍生物.进一步阐述了N—H键以及其邻位C—H键也能够和1,4-二卤-1,3-二烯反应,生成唑并吡啶衍生物.     

Vinylation of silanes and disiloxanes. Preparation of hexavinyldisiloxane

Vinylation of silanes and disiloxanes has been studied. It has been shown that in the reactions of silanes with vinyl chloride and magnesium or sodium the sole product formed is tetravinylsilane. In the reactions of hexaethoxydisiloxane with vinyl chloride and magnesium, tetravinylsilane is the sole product formed. Hexavinyldisiloxane with yield up to 85% is formed in the reaction of hexaethoxydisiloxane with vinyl chloride and magnesium in the presence of copper(II) salts as alkylation catalyst.     

One-Pot Vinylation of Secondary Phosphine Chalcogenides with Vinyl Sulfoxides

A facile, one-pot vinylation of secondary phosphine chalcogenides with alkyl(or aryl) vinyl sulfoxides has been elaborated. The vinylation comprises the nucleophilic addition of secondary phosphine chalcogenides to the vinyl sulfoxides (～50 mol% KOH, dioxane, 25–40°C, 1 h) followed by the elimination of sulfenic acids from the adducts (additional equivalent of KOH, 60–70°C, 1.5–2.0 h), the yields of target tertiary vinyl phosphine chalcogenides reaching 92%.     

Electrophilic Vinylation of Thiols under Mild and Transition Metal-Free Conditions

The iodine(III) reagents vinylbenziodoxolones (VBX) were employed to vinylate a series of aliphatic and aromatic thiols, providing E-alkenyl sulfides with complete chemo- and regioselectivity, as well as excellent stereoselectivity. The methodology displays high functional group tolerance and proceeds under mild and transition metal-free conditions without the need for excess substrate or reagents. Mercaptothiazoles could be vinylated under modified conditions, resulting in opposite stereoselectivity compared to previous reactions with vinyliodonium salts. Novel VBX reagents with substituted benziodoxolone cores were prepared, and improved reactivity was discovered with a dimethyl-substituted core.     

Vinylation and polymerization with trivinylaluminum. I. Vinylation of organic halides as a model for termination in cationic polymerization leading to vinyl end groups

An improved synthesis of trivinylaluminum (V₃Al) is described. The proton magnetic resonance (PMR) spectrum of V₃Al was recorded and analyzed. A new vinylation method involving the use of V₃Al as the vinylating agent has been developed, and the vinylation of organic halides by V₃Al was studied at ?30, ?50 and ?70°C. Primary alkyl chlorides, such as methyl and methylene chloride, do not react with V₃Al and were used as solvents. Secondary chlorides such as 2-chloropropane also do not react. t-Butyl chloride gives rise to t-butylethylene (70–98%), depending on reaction conditions, and the allylic chlorides, 3-chloro-1-butene, and 3-chloro-3-methyl-1-butene, yield the expected vinylated products and their isomers (～90%). Allyl and benzyl chloride do not react under the conditions tried. The reaction between V₃Al and the ditertiary dichloride 2,6-dichloro-2,6-dimethylheptane yields several isomeric C₁₃H₂₄ and C₁₁H₂₀ hydrocarbons; however, surprisingly, C₉H₁₆ does not form. The C₁₃ hydrocarbons arise by divinylation at the termini of the dichloride, while the C₁₁ hydrocarbons are formed by vinylation at one and proton elimination at the other terminus of the dichloride. The presence of unsaturated C₁₃H₂₄ and C₁₁H₂₀ isomers is most likely due to proton induced isomerization. These results are explained by a proximity effect involving vinylation at one end of the dichloride by V₃Al followed by rapid reaction of the second chlorine (mostly) by V₂AlCl generated in situ during the first vinylation in the proximity of the chloride. At the other chlorine terminus V₂AlCl causes either a second vinylation (leading to C₁₃ hydrocarbons) or a proton elimination (leading to C₁₁ hydrocarbons). The absence of C₉H₁₆ among the reaction products indicates that V₃Al exclusively effects vinylation. The RCl + V₃Al ← RV + V₂AlCl reaction may be regarded as a model for initiation followed by immediate termination in cationic olefin polymerization, a process leading to vinyl-ended polymers.