Fragmentation and rearrangement pathways in benzonorcaradiene photochemistry

Swenton, John S.; Krubsack, Arnold J.

doi:10.1021/ja01031a069

Cited by 18 publications

(11 citation statements)

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“…To the best of our knowledge, such a base‐induced process has not been described in the chemical literature, although thermal and photochemical carbene eliminations of cycloheptatriene and benzocyclopheptatriene derivatives have been reported 14a–14c. Photochemical carbene removal from benzo‐ and dibenzonorcaradienes has also been observed 15. The essential role of bromine in the above ring‐contraction process was demonstrated in a control experiment, in which dienes 16 and 17 were subjected to the same conditions as 18 : both hydrocarbons were isolated unchanged after the intended elimination process.…”

Section: Resultsmentioning

confidence: 95%

Annulation of Seven‐Membered Rings to [2.2]Paracyclophane

et al. 2008

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Section: Resultsmentioning

confidence: 95%

Annulation of Seven‐Membered Rings to [2.2]Paracyclophane

et al. 2008

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“…In this section, the photochemistry of 1a in terms of a kinetic model able to account for the experimental results of Figure is discussed. To rationalize the data, we basically resort (a) to a fit of the curves of Figure according to possible kinetic schemes, (b) to the photochemical reactivity of 1a resulting from ab initio modeling (see section ), and (c) to early results on the photochemical reactivity of 3b , − which, according to DFT calculations, can be envisaged as a product of the photochemical dissociation of 1a .…”

Section: Discussionmentioning

confidence: 99%

“…On one hand, it has been reported that 2a rearranges photochemically to 3b and not vice versa. On the other hand, there is a rich series of results regarding 3b and related systems − that give a substantial help for a plausible assignment of the intermediate product. In particular, irradiation for 2 h of a dilute solution of 3b gives nph as the major product (46%), unreacted 3b with a smaller percentage (36%), and other compounds, such as 1- and 2-methylnaphthalene and benzobicyclo[3.2.0]-2,6-diene, as minor products.…”

Section: Discussionmentioning

confidence: 99%

Photochemical Reactivity of 1,6-Methano[10]annulene

et al. 2017

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1,6-Methano [10]annulene solutions in cyclohexane have been subjected to continuous and pulsed UV irradiation. Photolysis occurs in both cases, giving naphthalene as a minor and major product, respectively. The wavelength dependence of the reaction in solution indicates that the photochemical process occurs, exciting 1,6-methano[10]annulene in the second and third singlet electronic excited states. The reaction kinetics has been determined under pulsed irradiation. From the time dependence of concentrations, along with support of density functional theory calculations and early published data, two mechanisms are proposed for naphthalene production. Reaction steps such as direct migration of the bridging methylene of 1,6-methano[10]annulene to cyclohexane and 1,6-methano[10]annulene isomerization to benzotropilidene have been identified. The calculated energy diagrams relative to the ground and lowest excited states allow one to relate these steps to processes such as electrocyclic closure and sigmatropic shift. The norcaradienic form of 1,6-methano [10]annulene results in the critical species for methylene migration and the sigmatropic [1,5] shift. The present results and those arising from photolysis in the gas phase are good examples of the photochemical reactivity of 1,6-methano[10]annulene.

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“…The photolysis of 2,5,7-triphenylnorcaradiene (26) in ether ( [a] As determined by the extent of insertion in alkanes and/or methanol.…”

Section: Carbenes From Fused-ring Cyclopropane Derivativesmentioning

confidence: 99%

Generation of Carbenes by Photochemical Cycloelimination

Griffin

1971

Angew. Chem. Int. Ed. Engl.

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A wide variety of shelf stable substrates undergo photochemical cycloelimination under relatively mild conditions. Suitable substrates include cyclopropanes, oxiranes, aziridines, and diazirines, as well as 3 H‐pyrazoles and 1,3‐dioxolanes. Carbenes prepared from these substrates as well as certain cyclic carbonates, sulfites, and phosphoranes behave chemically in a manner similar to divalent carbon species produced from conventional diazo precursors, namely, they react with alkenes to give cyclopropanes and undergo insertion into CH bonds of alkanes. In many cases the carbenes formed may also be detected by EPR and optical spectroscopic methods.

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Fragmentation and rearrangement pathways in benzonorcaradiene photochemistry

Cited by 18 publications

References 1 publication

Annulation of Seven‐Membered Rings to [2.2]Paracyclophane

Annulation of Seven‐Membered Rings to [2.2]Paracyclophane

Photochemical Reactivity of 1,6-Methano[10]annulene

Generation of Carbenes by Photochemical Cycloelimination

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