Cationic oligomerization of .ALPHA.-methylstyrene by chloroacetic acids.

Kimura, Takao; Mori, Masahiro; Hamashima, Motome

doi:10.1295/koron.43.9

Cited by 4 publications

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“…As a result, 2a was obtained as a major product with no formation of 1a in the case of the lower amount than 0.6 equivalent of HI. The formation of 2a was reported as one of the mixture of trimers in the reaction of α-methylstyrene with chloroacetic acid derivatives by Kimura et al Under our conditions, constitutional isomers of 2a were not found in 1 H NMR analysis. Collins et al synthesized 2a by the elimination of the corresponding alcohol .…”

Section: Resultsmentioning

confidence: 45%

Section: Resultsmentioning

confidence: 99%

“…When the counter anion I – acts as a base, dimer olefins 3 and 4 are formed (path b and c). Hofmann elimination proceeds to give less-substituted olefin 3 because of the bulkiness of a base (path c) . Cation A can be reacted toward less hindered olefin 3 to give the trimer cation D .…”

Section: Resultsmentioning

confidence: 99%

“…Hofmann elimination proceeds to give less-substituted olefin 3 because of the bulkiness of a base (path c). 14 Cation A can be reacted toward less hindered olefin 3 to give the trimer cation D. After deprotonation with I − , 2a is obtained. When methyl p-tolyl ketone exists in this system, the protonation with HI would be competitive with 2a and ketone.…”

Section: T H I S C O N T E N T Imentioning

confidence: 99%

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Selective Formation of Internal Olefinic Trimer of α-Methylstyrenes with HI Gas and Ketones

et al. 2018

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Reaction of α-methylstyrene in the presence of HI gas and methyl p -tolyl ketone selectively resulted in an internal olefinic trimer. We revealed that the ketones with the stabilization of the protonated state were efficient to give the corresponding trimers, whereas the other ketones gave the usual indane compound. From the investigation for the mechanistic path, we found that the trimer is a kinetic product and that indane is a thermodynamic product.

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Section: Resultsmentioning

confidence: 45%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: T H I S C O N T E N T Imentioning

confidence: 99%

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Selective Formation of Internal Olefinic Trimer of α-Methylstyrenes with HI Gas and Ketones

et al. 2018

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“…Surprisingly, competitve E 1 -elimination to form alkenes 10a and/or 10b , which might be expected in the presence of excess DtBMP, was not observed (Scheme ). This is all the more surprising in view of our unsuccessful attempts to generate ion-pair 6 independently via ionization of the corresponding 3° chloride.…”

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confidence: 99%

Isobutene Polymerization Using Chelating Diboranes: Reactions of a Hindered Pyridine with Carbocations Bearing α-Protons

et al. 2007

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Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

2023

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A series of exo‐olefin compounds ((CH3)2C(PhY)–CH2C(=CH2)PhY) were prepared by selective cationic dimerization of α‐methylstyrene (αMS) derivatives (CH2=C(CH3)PhY) with p‐toluenesulfonic acid (TsOH) via β‐C–H scision. They were subsequently used as reversible chain transfer agents for sulfur‐free cationic RAFT polymerization of αMS via β‐C–C scission in the presence of Lewis acid catalysts such as SnCl4. In particular, exo‐olefin compounds with electron‐donating substituents, such as a 4‐MeO group (Y) on the aromatic ring, worked as efficient cationic RAFT agents for αMS to produce poly(αMS) with controlled molecular weights and exo‐olefin terminals. Other exo‐olefin compounds (R–CH2C(=CH2)(4‐MeOPh)) with various R groups were prepared by different methods to examine the effects of R groups on the cationic RAFT polymerization. A sulfur‐free cationic RAFT polymerization also proceeded for isobutylene (IB) with the exo‐olefin αMS dimer ((CH3)2C(Ph)–CH2C(=CH2)Ph). Furthermore, telechelic poly(IB) with exo‐olefins at both terminals was obtained with a bifunctional RAFT agent containing two exo‐olefins. Finally, block copolymers of αMS and MMA were prepared via mechanistic transformation from cationic to radical RAFT polymerization using exo‐olefin terminals containing 4‐MeOPh groups as common sulfur‐free RAFT groups for both cationic and radical polymerizations.

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Cationic oligomerization of .ALPHA.-methylstyrene by chloroacetic acids.

Cited by 4 publications

References 0 publications

Selective Formation of Internal Olefinic Trimer of α-Methylstyrenes with HI Gas and Ketones

Selective Formation of Internal Olefinic Trimer of α-Methylstyrenes with HI Gas and Ketones

Isobutene Polymerization Using Chelating Diboranes: Reactions of a Hindered Pyridine with Carbocations Bearing α-Protons

Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

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