The norcaradiene–cycloheptatriene equilibrium

McNamara, Orla A.; Maguire, Anita R.

doi:10.1016/j.tet.2010.10.030

Cited by 102 publications

(77 citation statements)

References 209 publications

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“…The CHT–NOR 4a ⇌ 4b equilibrium has been substantially delineated by means of both physical and chemical methods (Scheme 2) [9–12]. …”

Section: Resultsmentioning

confidence: 99%

Palladium-catalyzed formation of oxazolidinones from biscarbamates: a mechanistic study

Kılbaş¹,

Balcı²

2011

Beilstein J. Org. Chem.

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SummaryOxazolidinones can be synthesized starting from cyclic biscarbamates via a palladium-catalyzed reaction. To test the proposed mechanism of this reaction, first, bicyclonorcarene endoperoxides derived from cyano and carbomethoxy cycloheptatrienes were synthesized and converted into the corresponding diols. The reaction of diols with toluenesulfonyl isocyanate followed by a palladium catalyzed reaction furnished oxazolidinone derivatives in similar yields. It was shown that, if one face of the double bond is blocked by substituents such as H or CN, the reaction also takes place. On the basis of these results, it was assumed that an antiperiplanar orientation of the metal and nucleophile is not necessary to form oxazolidinones. The metal is probably bonded to the allylic system from the same face as the nucleophile.

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“…The CHT–NOR 4a ⇌ 4b equilibrium has been substantially delineated by means of both physical and chemical methods (Scheme 2) [9–12]. …”

Section: Resultsmentioning

confidence: 99%

Palladium-catalyzed formation of oxazolidinones from biscarbamates: a mechanistic study

Kılbaş¹,

Balcı²

2011

Beilstein J. Org. Chem.

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“…On the contrary, C 2v attack is allowed if methylene is in the excited singlet state, promoting one electron from the σ bonding to the p nonbonding orbital. 44 In the 1a case, methylene departure from the decagonal ring is a two-step process, 19 leading first to the norcaradienic form 1b from 1a and second to methylene separation from the cyclopropane subunit of 1b, which is just the opposite of the abovementioned addition. The 1a → 1b rearrangement can be viewed as disrotatory electrocyclic closure of a polyenic chain The Journal of Physical Chemistry A Article with six π-electrons between C 1 and C 6 .…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

“…19 However, heating to 500°C , 1a isomerizes to 1,2-benzotropilidene (2a, Figure 1) rather than dissociating to yield methylene. 19,20 Only the 11,11-difluoro derivative of 1a gives almost quantitative naphthalene (nph) 20 upon pyrolysis at 450°C. In contrast, the photochemical reactivity of 1a has received less attention.…”

Section: Introductionmentioning

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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“…149 Maguire recently reviewed the factors that determine the distribution of norcaradiene and cycloheptatriene in various systems. 150 Qin also published a review paper on the application of cyclopropanation strategies to natural product synthesis 151 and an account about their own work on the synthesis of indole alkaloids by cyclopropanation. 152 the tropone- or tropolone-containing natural products in the following sections were not discussed in these reviews.…”

Section: Synthesis Of Naturally Occurring Tropones and Tropolonesmentioning

confidence: 99%

Synthesis of naturally occurring tropones and tropolones

et al. 2014

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Tropones and tropolones are an important class of seven-membered non-benzenoid aromatic compounds. They can be prepared directly by oxidation of seven-membered rings. They can also be derived from cyclization or cycloaddition of appropriate precursors followed by elimination or rearrangement. This review discusses the types of naturally occurring tropones and tropolones and outlines important methods developed for the synthesis of tropone and tropolone natural products.

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The norcaradiene–cycloheptatriene equilibrium

Cited by 102 publications

References 209 publications

Palladium-catalyzed formation of oxazolidinones from biscarbamates: a mechanistic study

Palladium-catalyzed formation of oxazolidinones from biscarbamates: a mechanistic study

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

Synthesis of naturally occurring tropones and tropolones

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