Phenyl Vinyl Ether Research Articles

Unraveling the Potential of Vinyl Ether as an Ethylene Surrogate in Heteroarene C─H Functionalization via the Spin-Center Shift.

Despite the simplicity and abundance of ethylene, its practical application presents significant hurdles due to its nature as a highly flammable gas. Herein, a strategic use of easily handled vinyl ether is reported as a latent ethylene surrogate achieved via a spin-center shift (SCS) pathway, enabling the successful three-component reaction that bridges heteroarenes and various coupling partners, including sulfinates, thiols, and phosphine oxides. Through a photoredox catalytic process, α-oxy radicals are generated by combining various radicals with phenyl vinyl ether, which are subsequently added to N-heteroarenes. Subsequently, the radical-mediated SCS pathway serves as the driving force for C─O bond cleavage, effectively engaging the phenoxy group as a leaving group. In addition, by broadening the utility of the method, a valuable synthon is provided for efficient C─H vinylation of N-heteroarenes following sulfonyl group elimination. This approach not only enriches the toolbox of synthetic methodology but also provides a more streamlined alternative, circumventing the challenges associated with direct ethylene gas usage. The versatility of the method, particularly evident in late-stage functionalizations of medicinally relevant molecules and peptides, underscores its capability to produce invaluable three-component compounds and vinylated N-heteroarene derivatives.

Passivation of poly-Si surface using vinyl and epoxy group additives for selective Si3N4 etching in H3PO4 solution

This work investigates the mechanism of polycrystalline silicon (poly-Si) dissolution in H3PO4. The etching rate of poly-Si was more rapid than that of silicon dioxide (SiO2) in H3PO4 solution, because poly-Si surface possesses unstable Si1+, Si2+, and Si3+ states – rather than Si4+, which is more stable. Additives such as epichlorohydrin, 1,2-epoxy-3-phenoxypropane, vinyl bromide, and phenyl vinyl ether with epoxy or vinyl groups were introduced into the H3PO4 to passivate the poly-Si surface. This significantly increased the presence of the Si4+ state and provided hydrophobic functional groups on the poly-Si surface to reduce the wettability of the poly-Si surface. The introduction of these additives significantly reduced the etching rate of poly-Si. 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl dimethoxymethylsilane, allyltrimethoxysilane, and vinyltrimethoxysilane with Si–O bonds, as well as epoxy or vinyl groups in their molecular structures, were demonstrated to suppress the etching rate of both SiO2 and poly-Si. The introduction of these additives to H3PO4 promoted the selective removal of silicon nitride (Si3N4) layers from multi-layered Si3N4/SiO2 trench structures without the loss of either poly-Si or SiO2.

Cationic Polymerization of Phenyl Vinyl Ethers: Investigations of the Propagation Mechanism, the Living Polymerization of Ortho-Substituted Derivatives, and the Step-Growth Polymerization of Divinyl Derivatives

The cationic polymerization of phenyl vinyl ether (PhVE) was investigated to elucidate the reason it is much more difficult to obtain high-molecular-weight polymers of PhVE than with alkyl vinyl et...

The phenyl vinyl ether-methanol complex: a model system for quantum chemistry benchmarking.

The structure of the isolated aggregate of phenyl vinyl ether and methanol is studied by combining a multi-spectroscopic approach and quantum-chemical calculations in order to investigate the delicate interplay of noncovalent interactions. The complementary results of vibrational and rotational spectroscopy applied in molecular beam experiments reveal the preference of a hydrogen bond of the methanol towards the ether oxygen (OH∙∙∙O) over the π-docking motifs via the phenyl and vinyl moieties, with an additional less populated OH∙∙∙P(phenyl)-bound isomer detected only by microwave spectroscopy. The correct prediction of the energetic order of the isomers using quantum-chemical calculations turns out to be challenging and succeeds with a sophisticated local coupled cluster method. The latter also yields a quantification as well as a visualization of London dispersion, which prove to be valuable tools for understanding the role of dispersion on the docking preferences. Beyond the structural analysis of the electronic ground state (S0), the electronically excited (S1) state is analyzed, in which a destabilization of the OH∙∙∙O structure compared to the S0 state is observed experimentally and theoretically.

An Atom‐Economic Approach for Vinylation of Indoles and Phenols Using Calcium Carbide as Acetylene Surrogate

An efficient N‐vinylation of indoles and O‐vinylation of phenols to give N‐vinyl indoles and phenyl vinyl ethers is reported. The vinylated products can be produced in satisfactory to excellent yields (65–92 %) upon treatment of indoles or phenols with calcium carbide in wet solvents in a standard laboratory setup. Key features of this reaction include the use of calcium carbide as a safe and inexpensive slow released acetylene source for N‐ and O‐vinylation under simple reaction conditions without the need for metal catalyst or halogenated substrates.

Synthesis of and catalytic nitrile hydration by a cationic tris(μ-hydroxo)diruthenium(II) complex having PMe3 ligands

While phenyl vinyl ether does not react with [Ru(η4-1,5-COD)(η6-1,3,5-COT)] (1)/PMe3, the C–O bond cleavage of phenyl vinyl ether occurs by 1/PMe3 in the presence of water to give a tris(μ-hydroxo)diruthenium(II) complex [(Me3P)3Ru(μ-OH)3Ru(PMe3)3]+[OPh]−·HOPh (3·HOPh) with evolution of ethylene. The molecular structure of 3·HOPh is unequivocally determined by X-ray analysis. The most likely mechanism for the formation of 3·HOPh is protonation of [Ru(η4-1,5-COD)(PMe3)3] (2c) by water and subsequent insertion of phenyl vinyl ether into the resulting Ru–H bond followed by the β-phenoxide elimination and hydrolysis and dimerization of the phenoxoruthenium(II) species. Complex 3 acts as a catalyst for nitrile hydration. As a typical example, the hydration of benzonitrile was achieved by 3 (1.0mol%) in 1,4-dioxane at 120°C for 6h to give benzamide quantitatively.

ChemInform Abstract: Radical Reactions of Alkyl 2‐Bromo‐2,2‐difluoroacetates with Vinyl Ethers: “Omitted” Examples and Application for the Synthesis of 3,3‐Difluoro‐GABA.

Abstract1‐Phenyl vinyl ether as well as 1‐ethoxystyrene do not yield the corresponding products.

Acid-catalyzed hydrolysis of lignin β-O-4 linkages in ionic liquid solvents: a computational mechanistic study

This work presents a computational mechanistic study of the acid-catalyzed hydrolysis of lignin β-O-4 linkages in ionic liquid solvents. Model compound 2-hydroyxyethyl phenyl ether undergoes dehydration to vinyl phenyl ether followed by hydrolysis to phenol and "Hibbert's ketones". Larger model compound α-hydroxy-phenethyl phenyl ether illustrates an E1 dehydration mechanism involving resonance-stabilized carbocations. Continuum models for ionic liquid solvents indicate that solvation can significantly affect the reaction rates. The tested continuum ionic liquid solvents give similar results, and differ significantly from continuum organic solvents with comparable dielectric constants. The acidic ionic liquid cation 1-H-3-methylimidazolium has lower predicted catalytic activity than hydronium or HCl, consistent with the former's relatively small acid dissociation constant. Calculations with dispersion-corrected density functionals give similar behavior. Calculations on Lewis acidic metal chlorides used experimentally for lignin hydrolysis suggest that the metal chloride may participate in the initial dehydration. These results provide a baseline for future studies of improved hydrolysis catalysts.

Effect of aromatic ring anisotropy on the 1H NMR shielding constants and conformational equilibrium of sterically strained aryl vinyl ethers

According to the 1H and 13C NMR data and quantum-chemical calculations, phenyl vinyl ether exists mainly in the s-trans conformation which is characterized by concurrent p-π* interaction of the oxygen atom with both unsaturated fragments. Introduction of two methyl groups into the ortho positions of the benzene ring forces the latter to go out from the vinyloxy group plane, leading to loss of p-π* conjugation with the aromatic ring, enhancement of p-π* conjugation with the vinyl group, and transition of the molecule to s-cis conformation. The 1H and 13C NMR data indicated that replacement of both o-methyl groups by tert-butyl makes the s-cis conformer sterically overcrowded even when the aromatic ring is oriented orthogonally with respect to the vinyl group; as a result, conformational equilibrium is displaced again toward s-trans rotamer.

Quantum chemical analysis of the structure and spectroscopic properties of aryl vinyl ethers

A series of aromatic vinyl ethers and some compounds close to them in structure are studied by DFT (B3LYP/6-311+G(2d,p)) and MP2(full)/6-311+G(2d,p) methods. Measurements of Raman spectra are also used. The calculation of vibrational spectra of aryl vinyl ether (AVE) isomers shows that stretching vibrations ν(C=C) are most conformation sensitive. The calculated value of I(C=C) for vinyl phenyl ether more than twice exceeds the corresponding value for vinyl methyl ether. The calculated and experimental values of I(C=C) are consistent with the hypothesis about the presence of a common conjugated π-system in the molecules of substituted AVEs. Here the bridging oxygen atom provides the π,p,π-interaction.

Synthesis of membranes of poly(vinyl ether)s and their gas permeability

AbstractCationic polymerizations of various vinyl ethers with cyclic substituents were performed with BF3OEt2. The polymers had relatively high molecular weight (Mn: 18,900–132,000), although the polymerization of phenyl vinyl ether did not proceed. According to differential scanning calorimetry, the obtained poly(vinyl ether)s showed higher glass transition temperatures than room temperature. These poly(vinyl ether)s gave free‐standing membranes both by a solution‐casting method and by a hot‐press method. In the membranes prepared by solution‐casting, the oxygen permeability coefficients of these membranes were in the range of 0.81–6.01 barrers, and poly(2‐adamanthyl vinyl ether) showed the highest gas permeability among them. Gas permeability of the membranes prepared by hot‐press was lower than that of the membranes prepared by solution‐casting. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

O-vinylacetoxime as a hydrogen bond acceptor

According to quantum chemical calculations (B3LYP/6-311G*) and IR spectroscopy the basicity of oxygen atom of O-vinylacetoxime is substantially lower than that of O-ethylacetoxime and is comparable to the basicity of phenyl vinyl and diphenyl ethers. In CCl4 solution, O-vinylacetoxime gives H-complexes wit methanol by formation of N···HO bonds. With phenol and trifluoroacetic acid under these conditions it enters in the reaction of electrophilic addition. O-Ethylacetoxime in inert media forms with methanol and phenol two types of H-complexes with the N···HO or O···HO bonds.

A Simple Method To Determine Kinetic Deuterium Isotope Effects Provides Evidence that Proton Transfer to Carbon Proceeds over and Not through the Reaction Barrier

A Simple Method To Determine Kinetic Deuterium Isotope Effects Provides Evidence that Proton Transfer to Carbon Proceeds over and Not through the Reaction Barrier

Studies on the catalysis of the reaction of organotin phenoxides with diethyl acetylenedicarboxylate

Different organotin phenoxides react at room temperature with diethyl acetylenedicarboxylate in diethyl ether, in the presence of lithium perchlorate to give a mixture of corresponding phenyl vinyl ethers and ring ethenylated phenols. Copyright © 2005 John Wiley & Sons, Ltd.

GC/MS Identification of Pyrolysis Products from 1,2-Bis(2,4,6-Tribromophenoxy)ethane

Despite the large amount of work carried out for the identification of pyrolytic products of fire retardant polymers, there is still lack of reliable MS data on halogenated substances. The development of toxic halogenated products mostly occurs during the process of pyrolysis, burning or recycling and they originate from the use of halogenated fire retardants. 1,2-Bis(2,4,6-tribromophenoxy)ethane is a common fire retardant used in acrylonitrile– butadiene–styrene terpolymers for computer housing. Its pyrolysis products (brominated vinyl phenyl ethers, brominated alkyl phenyl ethers, brominated diaryl ethers, polybrominated dibenzodioxins) from a 340 C pyrolysis have been identified by GC/MS and their mass spectra are presented and discussed. A mechanism accounting for the formation of the products is proposed.

A catalytic synthesis of thiosilanes and silthianes: palladium nanoparticle-mediated cross-coupling of silanes with thio phenyl and thio vinyl ethers through selective carbon-sulfur bond activation.

Palladium nanoparticles generated in situ from N,N-dimethyl-acetamide (DMA) solutions of PdX(2) (X = Cl(-), OAc(-), OCOCF(3)(-)) or Pd(2)(dba)(3) by reduction with alkyl silanes R(3)SiH (R = Me, Et, i-Pr, t-Bu) are selective catalysts for the cross-coupling of the silanes R(3)SiH with phenyl and vinyl thioethers forming the corresponding thiosilanes and silthianes in high yields and under mild conditions. The method is applicable to phenyl thioglycosides, giving access to thiosilyl glycosides a new class of sugar derivatives.

Acyl Iodides in Organic Synthesis: VI. Reactions with Vinyl Ethers

Reactions of acetyl iodide with butyl vinyl ether, 1,2-divinyloxyethane, phenyl vinyl ether, 1,4-di-vinyloxybenzene, and divinyl ether were studied. Vinyl ethers derived from aliphatic alcohols (butyl vinyl ether and 1,2-divinyloxyethane) react with acetyl iodide in a way similar to ethyl vinyl ether, i.e., with cleavage of both O–Csp2 and Alk–O ether bonds. From butyl vinyl ether, a mixture of vinyl iodide, butyl acetate, vinyl acetate, and butyl iodide is formed, while 1,2-divinyloxyethane gives rise to vinyl iodide, vinyl acetate, and 2-iodoethyl acetate. The reaction of acetyl iodide with divinyl ether involves cleavage of only one O–Csp2 bond, yielding vinyl acetate and vinyl iodide. In the reactions of acetyl iodide with phenyl vinyl ether and 1,4-divinyloxybenzene, only the O–CVin bond is cleaved, whereas the O–CAr bond remains intact.

Decomposition of vinyl ethers by alkalide K −, K +(15-crown-5) 2 via organopotassium intermediates

The structure of vinyl ethers determines the direction of the C–O bond cleavage by alkalide K −, K +(15-crown-5) 2 1. Highly reactive organopotassium compounds are intermediate products formed in the system containing phenyl vinyl ether, butyl vinyl ether, ethylene glycol butyl vinyl ether or triethylene glycol methyl vinyl ether. Vinylpotassium and butylpotassium react with 15-crown-5. The oxacyclic ring of the latter is opened in this case. Organopotassium ethers possessing CH 2CH 2O units eliminate ethylene. It results in various potassium alkoxides. The reaction of 1 with butyl vinyl ether occurs very slow as compared to other vinyl ethers and most of other reagents used till now.

Simple Preparation of N‐Benzyl‐β‐aminohydroxamic Acids by 1,3‐Dipolar Cycloaddition of Nitrones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Simple Preparation ofN-Benzyl-β-aminohydroxamic Acidsby 1,3-Dipolar Cycloaddition­ of Nitrones

β-Aminohydroxamic acids 6a-d are prepared in 4 steps and 30-45% overall yield from nitrones 1a-d by 1,3-dipolar cycloaddition with phenyl vinyl ether, N-benzylation, thermal rearrangement, and nucleophilic substitution of the formed phenyl ester with hydroxylamine.