Organic and polymer chemistry of electrophilic tri‐ and tetrasubstituted ethylenes

Hall, H. K.; Padías, Anne Buyle

doi:10.1002/pola.20190

Cited by 135 publications

(52 citation statements)

References 100 publications

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“…Diethylamino ring-substituted BCPP were used in preparation of photorefractive composites (6,7). It was shown that electrophilic tri-and tetrasubstituted olefins are particularly useful in delineating the transition from radical chemistry to ionic chemistry (8). Previous studies showed that TSE containing substituents larger than fluorine have very low reactivity in radical homopolymerization due to polar and steric reasons.…”

Section: Introductionmentioning

confidence: 99%

Novel copolymers of styrene. 13. Methyl and methoxy ring-trisubstituted butyl 2-cyano-3-phenyl-2-propenoates

Kharas

Gao

Clara

et al. 2016

Journal of Macromolecular Science, Part A

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Novel electrophilic trisubstituted ethylenes, methyl and methoxy ring-trisubstituted butyl 2-cyano-3-phenyl-2-propenoates, RPhCHDC(CN)CO 2 C 4 H 9 where R is 2,4,5-trimethyl, 2,4,6-trimethyl, 2,3-dimethyl-4-methoxy, 2,5-dimethyl-4-methoxy, 2,4-dimethoxy-3-methyl, 2,3,4-trimethoxy, 2,4,5-trimethoxy, 2,4,6-trimethoxy, 3,4,5-trimethoxy were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-trisubstituted benzaldehydes and butyl cyanoacetate, and characterized by CHN analysis, IR, 1 H and 13 C-NMR. All the ethylenes were copolymerized with styrene (M 1 ) in solution with radical initiation (ABCN) at 70 C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1 H and 13 C-NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200-500 C range with residue (2-5% wt), which then decomposed in the 500-800 C range.

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Section: Introductionmentioning

confidence: 99%

Novel copolymers of styrene. 13. Methyl and methoxy ring-trisubstituted butyl 2-cyano-3-phenyl-2-propenoates

Kharas

Gao

Clara

et al. 2016

Journal of Macromolecular Science, Part A

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“…It was shown that electrophilic tri- and tetrasubstituted ethylenes are particularly useful in delineating the transition from radical chemistry to ionic chemistry [7]. In regards to polymerization reactivity, previous studies showed that TSE containing substituents larger than ﬂuorine have very low reactivity in radical homopolymerization due to polar and steric reasons.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and styrene copolymerization of novel trisubstituted ethylenes: 3. Alkoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates

Kharas

Shinde

Jody

et al. 2018

Designed Monomers and Polymers

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Novel trisubstituted ethylenes, alkoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO2CH(CH3)2 (where R is 2-methoxy, 3-methoxy, 4-methoxy, 2-ethoxy, 3-ethoxy, 4-ethoxy, 4-propoxy, 4-butoxy, 4-hexyloxy) were prepared and copolymerized with styrene. The ethylenes were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and isopropyl cyanoacetate, and characterized by CHN analysis, FTIR, 1H and 13C NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by FTIR, 1H and 13C NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 250-500ºC range with residue (2.6–3.9% wt.), which then decomposed in the 500-800ºC range.

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“…The reaction pathway is dependent on the disparity in the energy levels of the participating HOMOÀLUMO orbitals, and also on the reaction conditions [4]. A case in point (Scheme 1) is the reaction of p-methoxystyrene (1) with dimethyl cyanofumarate (2). When the reaction is performed at high concentration, the monomers form the alternating copolymer 3, and the kinetics of this free-radical co-polymerization was studied in great detail [5].…”

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confidence: 99%

Cycloadditions of Bifunctional Vinyl Ethers with Electrophilic Alkenes through Tetramethylene Zwitterion Intermediates

May

Padías

Bates

et al. 2005

Helvetica Chimica Acta

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Dedicated to Professor Rolf Huisgen on the happy occasion of his 85th birthday Bifunctional vinyl ethers react with electron-poor alkenes to cyclobutanes in good yields. The second CC bond reacted with neither the cyclobutane nor its zwitterion intermediate, even on heating. Cyclobutanes formed from tetracyanoethylene (8) were transformed into tetrahydropyridines by reaction of the corresponding zwitterion with MeCN as the solvent. In contrast, cyclobutanes formed from dimethyl (dicyanomethylidene)propanedioate (9) did not react with MeCN, which is ascribed to diminished stabilization of the zwitterion intermediate, and increased steric effects. These results extend the classical studies of Huisgen and his co-workers.Introduction. ± The competition of both [2 2] and [2 4] cycloadditions with spontaneous polymerizations in reactions of electron-rich alkenes with electron-poor alkenes has long been of interest in our laboratory [1 ± 3]. The reaction pathway is dependent on the disparity in the energy levels of the participating HOMOÀLUMO orbitals, and also on the reaction conditions [4]. A case in point (Scheme 1) is the reaction of p-methoxystyrene (1) with dimethyl cyanofumarate (2). When the reaction is performed at high concentration, the monomers form the alternating copolymer 3, and the kinetics of this free-radical co-polymerization was studied in great detail [5]. When the same components at lower concentration are heated in MeCN, dihydropyran 4 is formed by an inverse-electron-demand [2 4] Diels ± Alder cycloaddition. When 2 and 3 are combined with Lewis acids (LiClO 4 or ZnCl 2 ) in Et 2 O, homopolymer 5 is obtained. And, finally, when the reaction is performed with ZnCl 2 in 2,5-dimethyltetrahydrofuran, [2 2]-cycloadducts 6 are formed exclusively, providing a good route to substituted cyclobutanes [3].During the spontaneous cycloadditions and polymerizations (charge-transfer polymerizations) that occur upon mixing electron-rich olefins with electron-poor vinyl monomers, colored charge-transfer complexes were involved in neither the initiation nor propagation step [4 ± 8]. The key initiator was the tetramethylene zwitterion ± diradical 7 originally proposed by Huisgen for [2 2] cycloaddition reactions [9] [10]. We proposed that 7 initiates polymerization, i.e., cationic homopolymerization if it is a zwitterion, and radical co-polymerization if it is a diradical. The larger the energy difference between the two olefins, the greater is the zwitterionic character of the intermediate. This paper describes a study of the cycloadditions between the electron-poor alkenes 2, 8, 9, or 10, and the electron-rich bifunctional vinyl ethers 11a ± 16a. This

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Organic and polymer chemistry of electrophilic tri‐ and tetrasubstituted ethylenes

Cited by 135 publications

References 100 publications

Novel copolymers of styrene. 13. Methyl and methoxy ring-trisubstituted butyl 2-cyano-3-phenyl-2-propenoates

Novel copolymers of styrene. 13. Methyl and methoxy ring-trisubstituted butyl 2-cyano-3-phenyl-2-propenoates

Synthesis and styrene copolymerization of novel trisubstituted ethylenes: 3. Alkoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates

Cycloadditions of Bifunctional Vinyl Ethers with Electrophilic Alkenes through Tetramethylene Zwitterion Intermediates

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