Allenyl Methyl Ether Research Articles

Insights into the mechanism, selectivity, and substituent effects in the Diels-Alder reaction of azatrienes with electron-rich dienophiles: An MEDT study

The reactivity and mechanistic intricacies of azatrienes in Diels-Alder reactions have been relatively unexplored despite their intriguing potential applications. In this study, we employ Molecular Electron Density Theory to theoretically investigate the hetero-Diels–Alder reaction involving azatrienes with ethyl vinyl ether and allenyl methyl ether. Analysis of Conceptual Density Functional Theory, energetic profiles, and the topological characteristics is conducted to elucidate the reactions. The revealed mechanism manifests as a polar one-step two-stages process under kinetic control. We establish a clear relationship of between the periselectivity, regioselectivity, and stereoselectivity on one hand and the characteristics of the reactions mechanism on the other hand. The influence of weak interactions on reaction activation barriers and bonding evolution are discussed in detail. We demonstrate that substituents enhancing the reverse electron density flux facilitate the feasibility of the reactions. The results lay ground for a meticulous control of the reaction of azatriene in similar synthetic scenarios.

ChemInform Abstract: Cross‐Coupling of Meyer—Schuster Intermediates under Dual Gold—Photoredox Catalysis.

Under dual gold/photoredox catalytic conditions, intermediates from the Meyer-Schuster rearrangement underwent an efficient cross-coupling with arene diazonium salts, leading to α-arylated enones. Diazonium salts assisted the dissociation of the propargyl hydroxyl group by forming alkoxydiazenes in the Meyer-Schuster rearrangement, and the coupling was proposed to proceed through an allenyl methyl ether.

Cross-Coupling of Meyer-Schuster Intermediates under Dual Gold-Photoredox Catalysis.

Under dual gold/photoredox catalytic conditions, intermediates from the Meyer-Schuster rearrangement underwent an efficient cross-coupling with arene diazonium salts, leading to α-arylated enones. Diazonium salts assisted the dissociation of the propargyl hydroxyl group by forming alkoxydiazenes in the Meyer-Schuster rearrangement, and the coupling was proposed to proceed through an allenyl methyl ether.

Mechanical Properties of the Dried and Swollen Gels Obtained from Poly (Ethylene Glycol Allenyl Methyl Ether)

Mechanical Properties of the Dried and Swollen Gels Obtained from Poly (Ethylene Glycol Allenyl Methyl Ether)

Synthesis of cross-linked polyethylene oxide-acetal macrocycles for solid superbase catalysts

A novel long-chain divinyl ether of tris(diethyleneglycol)-bisacetal, has been synthesized by electrophilic addition of one molecule of diethylene glycol to two molecules of divinyl ether of diethylene glycol (DVDEG) in the presence of CF3COOH in quantitative yield. The monomer was cationically polymerized (BF3·OEt2, or complex LiBF4·MeO(CH2)2OMe) and copolymerized with DVDEG to deliver solid polymers the yields being 80–100%. The polymers represent the cross-linked polyether-polyacetal structures comprising macrocycles. The polymers were treated with 3% solution of KOH or CsOH in methanol to afford solid superbase complexes of KOH (CsOH) with cross-linked polyether-polyacetal macrocyclic networks. Preliminary tests have shown the complexes to be active catalysts for ethynylation of acetones and prototropic isomerization of methyl propargyl ethers to allenyl methyl ethers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Modified copolymers of bifunctional vinyl ethers with methyl vinyl sulfide as active matrices of solid superbases

Reactive linear and crosslinked copolymers of diethylene glycol divinyl ether and ethylene glycol vinyl glycidyl ether with methyl vinyl sulfide have been synthesized in the presence of 2,2′-azobis(isobutyronitrile) (2%, 60 °C, 45–55 h) in ∼53% yield. The hydrolyzed at the residual vinyloxy and epoxy groups and oxidized at the methylthio groups copolymers upon treatment with KOH afford alkoxide (complex) and crown-like superbases. They are capable of catalyzing the acetone ethynylation, as well as the prototropic isomerization of methyl propargyl ether to allenyl methyl ether and vinylation of ethylene and diethylene glycols with acetylene.

Ab Initio Calculations of the Protonated Forms of Vinyl Methyl and Allenyl Methyl Ethers and Sulfides

The torsion potentials of the protonated forms of vinyl methyl and allenyl methyl ethers and sulfides were calculated by the ab initio HF, MP2, and B3LYP methods. The requirements to calculations of series of these compounds were established. It was confirmed that preferable protonation occurs on the \(\beta \)-carbon atom. Proton affinity energies were calculated. For allenyl methyl sulfide, rotamers may be formed in the gas phase under normal conditions.

Ozonolysis of Allenes and Alkylidenecyclopropanes (Homoallenes)

Allenyl methyl ether (1) and (diphenylmethylene)cyclopropane (5) were ozonized with an ozone/oxygen mixture. Formation of the observed products cannot be satisfactorily rationalized via the familiar modified Criegee mechanism. However, a single-electron transfer (SET) mechanism provides a simple rationale.

Preparation of end-?-allylnickel macroinitiator from poly(ethylene glycol) allenyl methyl ether and its application to the living coordination polymerization of isonitriles

An end-π-allylnickel macroinitiator (3) was prepared by the reaction of poly(ethylene glycol) allenyl methyl ether with an excess amount (5 equiv) of [(π-allyl)NiOCOCF3]2 (1) in the presence of PPh3 ([PPh3]/[1] = 1). The resulting macroinitiator was used as an initiator for the polymerization of 1-phenylethyl isonitrile (4a) to give a block copolymer [poly(ethylene glycol)-block-poly(4a)]. The molecular weight and composition of the block copolymers were controlled by the molecular weight of 3 and the ratio of 4a to 3. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 495–499, 2001

Electrical and magnetic properties of coordinated polymers of poly(ethylene glycol) allenyl methyl ether with iron chloride

The coordinated polymer of poly(ethylene glycol) alleneyl methyl ether (PEGA) with iron (III) chloride (PEGA-FeCl 3) was prepared by radical mechanism and characterized by infrared spectroscopy and elemental analyses. The electrical properties were studied using D.C. electrical conductivity. The relationship between the activation energy (ΔE) and the temperature are given to illustrate the behaviour of the polymer. Investigation of the A.C. magnetic susceptibility of the PEGA-FeCl 3 reveals that the sample obeys the Curie–Weiss law to about 100°C, and behaves in a metallic fashion at higher temperatures. A correlation between the conductivity and the magnetic susceptibility of the doped polymer is discussed.

Thermal decomposition behaviour of ethyl cellulose grafted copolymers in homogeneous media

The homogeneous grafting of both poly (ethylene glycol) allenyl methyl ether macromonomer (PEGA39), and 2-acrylamido-2-methylpropane sulphonic acid (AMPS) onto ethyl cellulose (EC) was carried out in benzene and benzene: ethanol (1 : 1 v/v ratio) solvent systems, respectively. The thermal decomposition behaviour of the grafted products, ethyl cellulose and homopolymers was investigated using TGA and DTG thermal methods. The thermal stability of the grafted products EC-g-PEGA39 are increased by increasing the macromonomer content, whereas the decomposition temperatures of the grafted products with AMPS (EC-g-AMPS) are decreased remarkably in most cases compared to those of ethyl cellulose and PAMPS. The activation energies of the decompositions are determined and related to the thermal stabilities of the various polymers.

Coordination of poly(diethylene glycol allenyl methyl ether) with some transition metal salts and characterization of the products

Coordinated polymers from poly(diethylene glycol allenyl methyl ether), (PDEGA),with Ni(II), Cu(II), Co(II) and Fe(III) salts have been prepared in ethanol solution of diethylene glycol allenyl methyl ether (DEGA) using AIBN as initiator. The coordinated polymers have been studied by elemental analysis and infrared spectroscopy. The IR spectral data of polychelates suggest that the metals are coordinated through the oxygen atoms of the diethylene glycol, and the oxygen atom of the methoxy group. Thermal behaviors of the coordinated polymers were studied by thermogravimetric analysis, and the order of stabilities is given. The activation energies of the polymers degradation are determined and discussed.

Characterization and evaluation of copolymers of end-allenoxy polyoxyethylene macromonomers and N-vinyl-2-pyrrolidone

Polyethylene glycol allenyl methyl ether macromonomers (M 1), having M̄ n=390 and 590 were copolymerized with N-vinyl-2-pyrrolidone (M 2) using AIBN as an initiator in benzene. The reactivity ratios were calculated based on a 1H NMR method, and their values are discussed. r 1 decreased from 0.64 to 0.12 and r 2 increased from 0.46 to 0.86 with increasing molecular weight of the macromonomers. Characterization of the polymers was performed by IR, NMR and GPC techniques. Thermal properties of the polymers were investigated by a TG/DTG method. The thermal stabilities of the copolymers are intermediate between those of the homopolymers and degradation occurs in three stages. The polymers have amphiphilic properties and are soluble in a variety of solvents including alcohols and water.

Copolymerization and Characterization of Ethylene Glycol Allenyl Methyl Ether with N-Vinyl Pyrrolidone

The radical copolymerization of monoethylene glycol allenyl methyl ether (MEGA), with N-vinyl pyrrolidone (Vp) were investigated at various compositions using AIBN as initiator at 60°C. The composition of the copolymers were characterized by 1H NMR, IR and GPC techniques. Values of reactivity ratios were determined using NMR methods, r1 (MEGA) = 0.41 ± 0.05 and r2 (VP) =0.765 ± 0.08 calculated. Thermal stability and degradation behavior of the polymers were examined using TG/DTG methods. The thermal stability of the copolymers were intermediate between those of the two homo-polymers, and appear to degrade in two stages. The first stage resulting from decomposition of C-O bonds of the side chain and the C-C bonds β to double bonds of PMEGA units. The second stage resulted from decomposition of the pyrrolidone ring of PVP units.

Radical copolymerizability of end-allenoxy polyoxyethylenes with styrene

Radical copolymerizabilities of poly(ethylene glycol) allenyl methyl ether ( 2a and 2b, the number average molecular weight ( M n) = 390 and 590, receptively) were evaluated by the copolymerization with styrene monomer ( St). The relative reactivities of macromonomers have been decreased as the length of the oxyethylene side chains in the macromonomer increased, and were estimated to be r 1 = 2.5 ± 0.1, r 2 = 0.96 ± 0.2 for 2a and r 1 = 1.4 ± 0.1, r 2 = 2.4 ± 0.3 for 2b.

Thermal degradation studies of poly(ethylene glycol allenyl-methyl ether)s and their copolymers with styrene

The thermal degradation behaviours of poly(ethylene glycol allenyl methyl ether) (PEGA), poly(ethylene glycol allenyl methyl ether) macromonomer, Mn590, (PEGA590), and their copolymers with styrene at various compositions were investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). The homopolymers and copolymers exhibit a one step degradation curve. The thermal stabilities of the copolymers are intermediate between those of the two homopolymers. PEGA exhibits low thermal stability resultant from the thermal instabilities of the CO bonds of the side chains and the CC bonds β to the double bonds of the polymer.

Synthesis and radical polymerization of end-allenoxy polyoxyethylene macromonomer

Poly(ethylene glycol) allenyl methyl ether ( 2) was prepared by the reaction of poly(ethylene glycol) monomethyl ether (the number average molecular weight ( M n) = 550) with propargyl bromide, followed by the base-catalyzed isomerization reaction. Functionality of end-allenyl groups in the obtained macromonomer was determined as 92% (from 1H-NMR). The radical polymerization of 2 was carried out in bulk and in benzene at 60 or 120°C to yield a polymer with poly(ethylene glycol) side chains. For instance, a polymer ( 3, M n = 3900) was obtained in 39% yield by the polymerization of 2 in bulk at 60°C for 48 h using 6 mol% of α,α′-azobisisobutyronitrile (AIBN). The obtained polymer was soluble in organic solvents as well as water.

Block copolymerization of alkoxyallenes by the living coordination system with a π‐allylnickel catalyst

AbstractBlock copolymers of alkoxyallenes were obtained in high yield by the two‐stage living coordi‐nation polymerization of two kinds of alkoxyallenes using an allylnickel catalyst. The resulting copolymers had narrow molecular weight distributions (∼ 1.1), regardless of the order of the monomer additions. When an alkoxyallene‐bearing hydrophilic substituent was used as a co‐monomer for the block copolymerization with that bearing a hydrophobic one, the resulting copolymer showed amphiphilic properties. For example, a block copolymer obtained by the copolymerization of n‐hexyloxyallene with diethylene glycol allenyl methyl ether was soluble in water as well as n‐hexane. © 1995 John Wiley & Sons, Inc.

Electron-impact-induced 3,3-sigmatropic rearrangement and cyclization in phenyl allenylmethyl ethers

A 3,3-sigmatropic rearrangement in the M(+·) of phenyl allenylmethyl ether is proposed for the observed losses of CO, C2H4, and CH3. Direct cyclization in the M(+·) also leads to the [M-CH3] ion. The presence of sulfur as the heteroatom in phenyl allenylmethyl sulfide does not significantly influence the occurrence of Claisen rearrangement. Ortho interaction of the nitro group with the allenyl double bond in the side chain leads to characteristic fragment ions in 2-nitrophenyl allenylmethyl ether. Linked scans, high-resolution mass spectrometry, collision-activated dissociation-B/E linked-scan spectra, and D-labeling have been employed to support the proposed mechanisms and ion structures.

ChemInform Abstract: Radical Cyclization of o‐Haloaryl Allenylmethyl Ethers and Amines: Synthesis of 3‐Ethenyl‐2,3‐dihydrobenzofurans and 3‐Ethenyl‐2,3‐ dihydroindoles.

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