Ring opening reactions of benzocyclobutene and derivatives

Jensen, Frederick R.; Coleman, William E.; Berlin, Alvin J.

doi:10.1016/s0040-4039(00)62034-8

Cited by 37 publications

(14 citation statements)

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“…BCBMA was synthesized according to the synthetic route as shown in Scheme , namely, benzyne was derived from benzenediazonium carboxylate obtained by diazotizing anthranilic acid, and then 1‐acetoxybenzocyclobutene was synthesized by the addition of vinyl acetate. The obtained 1‐acetoxybenzocyclobutene was hydrolyzed with p ‐toluenesulfonic acid to synthesize 1‐hydroxybenzobutene.…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that benzocyclobutene (BCB), which is stable at room temperature, undergoes thermal isomerization to form highly reactive o ‐quinodimethane at more than 200 °C . The o ‐quinodimethane has been known as quite reactive species, which can undergo a Diels–Alder reaction with the double bond from another molecule in the presence of external dienophile .…”

Section: Introductionmentioning

confidence: 99%

“…INTRODUCTION It has been reported that benzocyclobutene (BCB), which is stable at room temperature, undergoes thermal isomerization to form highly reactive o-quinodimethane at more than 200 C. [1][2][3][4][5][6] The o-quinodimethane has been known as quite reactive species, which can undergo a Diels-Alder reaction with the double bond from another molecule in the presence of external dienophile. [6][7][8][9][10][11] Whereas the o-quinodimethane also functions as dienophile when external dienophile is absent, leading to the production of dibenzocyclooctadiene and/or poly(o-xylylene) via the spiro dimer by the self-Diels-Alder reaction (Scheme 1).…”

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confidence: 99%

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Synthesis of polymethacrylate‐bearing benzocyclobutene structure and extension to networked polymer based on thermal isomerization

Komeda

Shintaro

Yoshida

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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1‐Benzocyclobutenyl methacrylate‐bearing methacrylate (BCBMA) backbone has been synthesized, and radical polymerization of the monomer was performed by utilizing 2, 2′‐azobisisobutyronitrile (AIBN) as initiator to result poly‐BCBMA. Differential scanning calorimetry (DSC) measurement of the derived poly‐BCBMA revealed the lowering of thermal isomerization temperature from that of nonsubstituted benzocyclobutene. The thermal decomposition temperature of BCBMA before and after thermal treatment was confirmed by thermogravimetric analysis (TGA). The results of the TGA observation did not show significant difference in both 5% and 10% weight loss temperature (Td5 and Td10). This result suggests that the thermal conversion of the poly‐BCBMA to the networked polymer take place without thermal decomposition of the main chain based on the methacrylate framework. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2175–2180

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Synthesis of polymethacrylate‐bearing benzocyclobutene structure and extension to networked polymer based on thermal isomerization

Komeda

Shintaro

Yoshida

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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“…They were originally obtained by the double elimination of a,a 0 -dibromo-ortho-xylenes [1] or by thermal opening of the corresponding benzocyclobutenes [2,3], and several reviews emphasised the importance of these transients as tools for the synthesis of cyclic organic compounds [4][5][6][7][8][9]. An interesting reaction was the direct formation of the naphthalene derivatives 2 by Diels-Alder reaction with dibromo-ortho-xylylene 1 (generated from tetrabromoxylene) with spontaneous loss of HBr [1,10,11] (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

ortho-Quinodimethane from anthracene epidioxide: Scope of the Diels–Alder reaction and mild preparation of naphthalene derivatives

Siret

Albrecht

Defoin

2014

Comptes Rendus. Chimie

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“…The o-quinodimethane undergoes Diels-Alder reactions, and in the absence of an external dienophile, generates 1,2,5,6-dibenzocyclooctane (~25%) and higher oligomers (~75%) (Scheme 1). 4,5 Since the thermally unstable spirodimer does not generate any 1,2,5,6-dibenzocyclooctane upon heating, it apparently forms by a different mechanism than the oligomers. 5 This thermal activation and the lack of condensation byproducts makes benzocyclobutene chemistry especially attractive for crosslinking 6 and for polymer-forming reactions 3 by a step (condensation-like) mechanism.…”

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Synthesis of a Polymerizable Benzocyclobutene that Undergoes Ring-Opening Isomerization at Reduced Temperature

Pugh

Baker

Storms

2013

Synlett

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1-Ethoxyvinylbenzocyclobutene is a substituted benzocyclobutene that undergoes radical polymerization to produce polymers that can be crosslinked at 100-150°C. The 4-and 5-vinyl isomers are synthesized in a 1:4 ratio via a halogenated benzyne intermediate produced from anthranilic acid, followed by cycloaddition with ethyl vinyl ether and replacement of the halogen atom with a vinyl group.Key words: benzocyclobutene, cycloaddition, ring-opening isomerization, Kumada coupling, benzyne Bicyclo[4.2.0]octa-1,3,5-triene, or benzocyclobutene (BCB), 1,2 has been widely used in polymer science based on the ring-opening ability of the strained cyclobutene ring. 3It is stable at room temperature, but undergoes an electrocyclic rearrangement at elevated temperature (>200°C) to the highly reactive o-quinodimethane. The o-quinodimethane undergoes Diels-Alder reactions, and in the absence of an external dienophile, generates 1,2,5,6-dibenzocyclooctane (~25%) and higher oligomers (~75%) (Scheme 1). 4,5Since the thermally unstable spirodimer does not generate any 1,2,5,6-dibenzocyclooctane upon heating, it apparently forms by a different mechanism than the oligomers. 5 This thermal activation and the lack of condensation byproducts makes benzocyclobutene chemistry especially attractive for crosslinking 6 and for polymer-forming reactions 3 by a step (condensation-like) mechanism. Benzocyclobutene-containing vinyl monomers have also been polymerized by chain mechanisms. 7-10Although the high temperature of the ring-opening isomerization reaction is useful for applications such as the crosslinking of engineering polymers, which are synthesized at elevated temperatures, it also limits the use of benzocyclobutene in other applications, such as those involving temperature-sensitive materials. For example, it would be difficult to exploit the benzocyclobutene crosslinking reaction to create nanostructured flexible films by field-assisted roll-to-roll processing if the glass transition temperature of the substrate polymer film and/or the available thermal field are significantly less than 200°C. We are particularly interested in developing nanostructured flexible films using block copolymers that can be aligned and crosslinked at more reasonable temperatures than those used to crosslink benzocyclobutene. Scheme 1 Electrocyclic ring-opening of benzocyclobutene and its subsequent [4+2] cycloaddition with another o-quinodimethane 4The ring-opening isomerization temperature of benzocyclobutenes can be lowered by introducing both electrondonating (raises the ground state energy) and electronwithdrawing (lowers the transition state energy) substituents onto the cyclobutene ring. 5For example, 1-methoxybenzocyclobutene isomerizes at ≥110°C, 11 and the cyclobutene rings of poly(1-benzocyclobutenyl vinyl ether) isomerize at ≥60°C. 12(The temperature range over which the exothermic isomerization transitions occur is usually broad.) Block copolymers with controlled chain lengths are prepared by chain polymerizations, such as living ...

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Ring opening reactions of benzocyclobutene and derivatives

Cited by 37 publications

References 5 publications

Synthesis of polymethacrylate‐bearing benzocyclobutene structure and extension to networked polymer based on thermal isomerization

Synthesis of polymethacrylate‐bearing benzocyclobutene structure and extension to networked polymer based on thermal isomerization

ortho-Quinodimethane from anthracene epidioxide: Scope of the Diels–Alder reaction and mild preparation of naphthalene derivatives

Synthesis of a Polymerizable Benzocyclobutene that Undergoes Ring-Opening Isomerization at Reduced Temperature

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