New and facile substitution reactions at tertiary carbon. The m-nitrocumyl system

Kornblum, Nathan; Davies, Thomas M.; Earl, Gary W.; Holy, Norman L.; Manthey, Joseph W.; Musser, Michael T.; Swiger, R. Thomas

doi:10.1021/ja01024a052

Cited by 12 publications

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“…One is the expected C-substitution product. The other is an unstable compound which decomposes into the 4-nitrocumyl alcohol during workup and may thus be ascribed to O-substitution . With 4-nitrobenzyl derivatives, the C-substitution product is considered to result from the S RN 1 reaction and the O-substitution product from a S N 2 substitution 1a…”

Section: Resultsmentioning

confidence: 99%

“…(a) The O-substitution product is also obtained, albeit in lesser yield, upon reaction with the lithium salt of 2-nitropropanate 8b. Ion pairing of the negative end of the 2-nitropropanate ion by the countercation is expected to be stronger with Li + than with (CH 3 ) 4 N + , thus explaining why the percentage of O-alkylation is less in the first case than in the second.…”

Section: Referencesmentioning

confidence: 99%

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“Thermal” S_RN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

et al. 1999

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In SRN1 reactions, unlike in conventional nucleophilic substitutions, the nucleophile does not react directly with the electrophile but with a radical resulting from its reductive cleavage. Many SRN1 substitutions require an external stimulation involving the injection of a catalytic amount of electrons. In “thermal” SRN1 reactions, there is no other source of initiating electrons than the nucleophile which is usually a poor electron donor. Such reactions are unlikely to be initiated by a simple outersphere electron transfer from the nucleophile followed by the cleavage of the substrate anion radical. Rather, initiation follows a mechanism in which electron transfer and bond cleavage are concerted. These conclusions are based on a full analysis of a model system involving 4-nitrocumyl chloride as the substrate and the 2-nitropropanate ion as the nucleophile where all the pertinent thermodynamic and kinetic parameters were determined by direct or indirect electrochemical methods. They extend to other examples of thermal SRN1 reactions reported earlier. These results provide new and unambiguous evidence that a decrease in driving force is able to change the mechanism of homogeneous reductive cleavage reactions from stepwise to concerted. The observation of this mechanism change was made possible by the kinetic amplification offered by the chain character of the SRN1 process, which allows the investigation of very slow electron transfers resulting from very low driving forces, that would have otherwise escaped characterization.

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Section: Resultsmentioning

confidence: 99%

Section: Referencesmentioning

confidence: 99%

“Thermal” S_RN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

et al. 1999

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Nucleophilic Substitution of Thiophene Derivatives

Spinelli¹,

Consiglio²,

Dell’Erba³

et al. 1991

Chemistry of Heterocyclic Compounds: A Series of Monographs

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Radikal‐Anionen als Zwischenstufen in der Organischen Chemie

Holy

Marcum

1971

Angewandte Chemie

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SchluBDie Zahl der Arbeiten, in denen systematisch der EinfluR der Liganden auf die katalytische Aktivitat eines u b e rgangsmetall-Katalysators untersucht wurde, ist noch verhaltnisma8ig klein. Solange eine breite experimentelle Basis fehlt, ist sicher auch eine gelegentliche Fehlinterpretation nicht ganz auszuschlieRen. In diesem Sinne sei dieser Fortschrittsbericht in erster Linie als Anregung verstanden. Es ware uns eine Genugtuung, wenn durch ihn hier und dort systematische Forschung initiiert wurde, die das Verstandnis dieser fur das gesamte Gebiet der Katalyse an ubergangsmetallen so wichtigen Zusammenhange vertiefen helfen konnte.

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New and facile substitution reactions at tertiary carbon. The m-nitrocumyl system

Abstract: 7) Presumably, the alcohol derives from the oxygen alkylate, but (8) In addition, m-nitro-cu-methylstyrene is isolated in 12 Z yield.(9) These and other differences are discussed briefly in the accompanying communication:

Cited by 12 publications

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“Thermal” S_RN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

“Thermal” S_RN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

Nucleophilic Substitution of Thiophene Derivatives

Radikal‐Anionen als Zwischenstufen in der Organischen Chemie

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New and facile substitution reactions at tertiary carbon. The m-nitrocumyl system

Abstract: 7) Presumably, the alcohol derives from the oxygen alkylate, but (8) In addition, m-nitro-cu-methylstyrene is isolated in 12 Z yield.(9) These and other differences are discussed briefly in the accompanying communication:

Cited by 12 publications

References 0 publications

“Thermal” SRN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

“Thermal” SRN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

Nucleophilic Substitution of Thiophene Derivatives

Radikal‐Anionen als Zwischenstufen in der Organischen Chemie

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Product

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“Thermal” S_RN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers

“Thermal” S_RN1 Reactions: How Do They Work? Novel Evidence that the Driving Force Controls the Transition between Stepwise and Concerted Mechanisms in Dissociative Electron Transfers