Mechanism of the Reaction of Atomic Carbon with Pyrrole. Evidence for the Intermediacy of a Novel Dehydropyridinium Ylide

Emanuel, Calvin J.; Shevlin, Philip B.

doi:10.1021/ja00092a069

Cited by 38 publications

(32 citation statements)

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“…[12] The active role of II in the reaction of gaseous atomic carbon with pyrrole has also been ascertained. [15] Considering the above, it is not surprising that isomerisation of pyridines to metal C-coordinated species derived from II-IV is a very rare rearrangement, despite the stabilisation that their carbene resonance contributors may provide (e.g., II b for the 2-isomer II). Prior to our work, a 2,6lutidinium ylide bound to osmium(II) through the paracarbon atom (therefore related to IV) was produced by Cordone and Taube from an isomeric N-bound 2,6-lutidine complex through a h 2 -C,C-2,6-lutidine species intermediate.…”

Section: Introductionmentioning

confidence: 99%

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Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e⁻ Unsaturated [Tp^Me2Ir^III(C₆H₅)₂] Moiety

Conejero

López‐Serrano

Paneque

et al. 2012

Chemistry A European J

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Section: Introductionmentioning

confidence: 99%

“…More recently II has been generated in the gas phase by Schwarz and co‐workers, who have additionally shown that it is stable on the microsecond timescale 12. The active role of II in the reaction of gaseous atomic carbon with pyrrole has also been ascertained 15…”

Section: Introductionmentioning

confidence: 99%

Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e⁻ Unsaturated [Tp^Me2Ir^III(C₆H₅)₂] Moiety

Conejero

López‐Serrano

Paneque

et al. 2012

Chemistry A European J

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“…Recently, Shevlin et al [16] have postulated aza-and thiacyclohexatrienes 6 as intermediates in the reaction cascades that follow the addition of carbon atoms to pyrroles and thiophene, respectively. Based on the observed products and on preliminary calculations, they favour the ylide structure 6b for the nitrogen derivatives and the allene structure 6a…”

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confidence: 99%

3δ2-Chromene (2,3-Didehydro-2H-1-benzopyran): Generation and Interception

Christl¹,

Drinkuth

1998

Eur. J. Org. Chem.

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The treatment of 3‐bromo‐2H‐chromene (7), dissolved in furan, 2‐methylfuran, or 2,5‐dimethylfuran, with potassium tert‐butoxide, leads to formation of the epoxybenzo[c]chromene derivatives 8−11 in yields of 28−59%. Likewise, in styrene solution, exo‐2‐phenylcyclobuta[b]chromene 12 is produced (41% yield). With tetrahydrofuran as the solvent, 2‐tert‐butoxy‐2H‐chromene (13) is observed as the only product (79% yield). From these results, it is concluded that 7 is converted by β‐elimination into the title compound 5. This reactive intermediate is then intercepted by the furans and styrene in cycloaddition reactions to give compounds 8−12, whereas reaction with KOtBu/HOtBu transforms it to the acetal 13. The epoxybenzochromenes 8, 9, and 11 rearrange on heating at 110°C to give the epoxyxanthene derivatives 16−18.

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“…In terms of the proposed mechanism this is explained by rearrangement of the 1,3-zwitterionic intermediate into the 1,2-zwitterion. Such a rearrangement had already been described in the literature for the case of pyridine systems; the 1,2-zwitterion is regarded as more stable [90]. The diethylamino group leaves in the form of the imine, giving up a proton to the negatively charged carbon atom.…”

Section: + +mentioning

confidence: 84%

Methods for the synthesis of cinnolines (review)

Vinogradova

Балова

2008

Chem Heterocycl Comp

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This review analyses the principal approaches to the synthesis of the cinnoline nucleus, used as synthetic precursors of arenediazonium salts, arylhydrazones, and arylhydrazines, and also reductive methods for the synthesis of polycondensed derivatives of cinnoline. The mechanisms of the transformations and the possibilities and limitations of the various methods are discussed. Special attention is paid to methods based on the cyclization of derivatives of arenediazonium salts, which have been developed substantially in recent years.

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Mechanism of the Reaction of Atomic Carbon with Pyrrole. Evidence for the Intermediacy of a Novel Dehydropyridinium Ylide

Cited by 38 publications

References 0 publications

Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e⁻ Unsaturated [Tp^Me2Ir^III(C₆H₅)₂] Moiety

Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e⁻ Unsaturated [Tp^Me2Ir^III(C₆H₅)₂] Moiety

3δ2-Chromene (2,3-Didehydro-2H-1-benzopyran): Generation and Interception

Methods for the synthesis of cinnolines (review)

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Mechanism of the Reaction of Atomic Carbon with Pyrrole. Evidence for the Intermediacy of a Novel Dehydropyridinium Ylide

Cited by 38 publications

References 0 publications

Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e− Unsaturated [TpMe2IrIII(C6H5)2] Moiety

Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e− Unsaturated [TpMe2IrIII(C6H5)2] Moiety

3δ2-Chromene (2,3-Didehydro-2H-1-benzopyran): Generation and Interception

Methods for the synthesis of cinnolines (review)

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Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e⁻ Unsaturated [Tp^Me2Ir^III(C₆H₅)₂] Moiety

Tautomerisation of 2‐Substituted Pyridines to N‐Heterocyclic Carbene Ligands Induced by the 16 e⁻ Unsaturated [Tp^Me2Ir^III(C₆H₅)₂] Moiety