Substitution of Polynuclear Aromatic Compounds. I. The Friedel-Crafts Benzoylation of Naphthalene

Jensen, Frederick R.

doi:10.1021/ja01562a051

Cited by 14 publications

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“…91,92 This is probably one of the reasons that investigations of isomer distributions, at times, have given confusing and contradictory results. 92 In the case of acetylation of xylene, for example, the regioisomer distribution was independent of the reaction conditions like the mode of addition of the reagents. 91 In the case of acetylation of naphthalene, 91 the ratio of Rand β-substituted products was 99/1 when the acetylating agent and naphthalene in the solvent were added slowly to a slurry of AlCl 3 (Table 4, entry 4); in contrast, it was 7/93 when the acetylating agent and AlCl 3 in the solvent were added slowly to naphthalene (Table 4, entry 5).…”

Section: Resultsmentioning

confidence: 99%

“…The regioselectivity in F−C reactions can be strongly dependent upon variables like the mode of addition of reagents, total concentration of reactants/promotor, and types of Lewis acid promotor and solvent. , This is probably one of the reasons that investigations of isomer distributions, at times, have given confusing and contradictory results . In the case of acetylation of xylene, for example, the regioisomer distribution was independent of the reaction conditions like the mode of addition of the reagents .…”

Section: Resultsmentioning

confidence: 99%

“… g Only one reasonable position indicated by the software. h AcCl (1.0 equiv) and AlCl 3 (1.0 equiv) in dichloroethane were added to a solution of naphthalene in dichloroethane (1.0 equiv) at 25 °C i AlCl 3 -promoted reaction with benzoyl chloride and naphthalene in dichloroethane at 25 °C (different stoichiometric relationships) j Refluxing the substrate with AcCl (1.1 equiv) and AlCl 3 (2.3 equiv) in 1,2-dichloroethane …”

Section: Resultsmentioning

confidence: 99%

“… i AlCl 3 -promoted reaction with benzoyl chloride and naphthalene in dichloroethane at 25 °C (different stoichiometric relationships) …”

Section: Resultsmentioning

confidence: 99%

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Validation of a Computational Model for Predicting the Site for Electrophilic Substitution in Aromatic Systems

et al. 2010

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We have investigated the scope and limitations of a method for predicting the regioisomer distribution in electrophilic aromatic substitution reactions that are under kinetic control. This method is based on calculation of the relative stabilities of the sigma-complex intermediates using density functional theory. Predictions from this method can be used quantitatively for halogenations; it agreed to an accuracy of about 1 kcal/mol with experimental observations in 10 of the 11 investigated halogenation reactions. For nitrations, the method gave useful predictions for heterocyclic substrates. The method failed for nitration of monosubstituted benzenes, and we expect that more elaborate model systems, including explicit solvent molecules, will be necessary to obtain quantitatively useful predictions for such cases. For Lewis acid promoted Friedel-Crafts acylations, the method can be expected to give qualitatively correct predictions, that is, to point out the dominating isomer. For substrates where the regioisomeric outcome is highly dependent on the reaction conditions, the method can only be of qualitative use if the concentration of the free Lewis acid is high during the reaction. We have also compared the predictive capacity of the method to that of a modern reactivity index, the average local ionization energy, I(r). The latter method is found to predict the regisolectivity in halogenations and nitrations qualitatively correctly if the positions for the I(r) minima (I(S,min)) are not too sterically hindered but fails for qualitative predictions of F-C reactions. The downscaled I(S,min) values also perform well for the quantitative prediction of regioisomer distributions of halogenations. The accuracy is slightly lower than that for the new method.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“… i AlCl 3 -promoted reaction with benzoyl chloride and naphthalene in dichloroethane at 25 °C (different stoichiometric relationships) …”

Section: Resultsmentioning

confidence: 99%

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Validation of a Computational Model for Predicting the Site for Electrophilic Substitution in Aromatic Systems

et al. 2010

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Baddeley Isomerization

2010

Comprehensive Organic Name Reactions and Reagents

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Migration of alkyl groups in polyalkylbenzenes or polynuclear aromatic compounds in the presence of anhydrous aluminum chloride or the mixture of protonic acid and Lewis acid has been reported in the Baddeley isomerization reaction. It has been found that the amount of α‐isomer can be reduced by the addition to the reaction mixture of a variety of substances (e.g., nitrobenzene and excess acid chloride) that complex strongly with aluminum chloride. Similarly, less α‐isomer has been observed when this reaction is carried out in nitrobenzene. Isomerization of hindered aromatic ketones has been observed when ketones are melted with an excess amount of aluminum chloride and sodium chloride.

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The Friedel‐crafts acylation reaction. II. A study of the Hammett relationship in the Friedel‐crafts benzoylation of toluene with substituted benzoyl chlorides.

Slootmaekers¹,

Rasschaert²,

Janssens³

1966

Bulletin des Soc Chimique

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Dans l'etude de l'effet de substituant dans la reaction d'acylation du toluene par des chlorures de benzoyle substituds en meta ou en para, on constate que les rhctivitds de ces derniers, relatives au chlorure de benzoyle non substitud, ne sont pas correlbs par l'kquation de Hammett.I1 est montrk que la distribution des isomeres dans le produit de rhction de chaque membre de la skrie de rhctions est pratiquement constante, et que la sdrie de rkctions est caracteri&e par une relation isocinktique. Par ailleurs, pour expliquer la ddviation a l'huation de Hammett, on ne peut invoquer ni une diffkrence dans la polaritk du milieu reactionnel pour chaque membre de la skrie de reactions, ni une ddpendance de la valeur de In constante des substituants de Hammett de la nature du solvant employe (le chlorobenzene).Les rbultats sont alors discutbs en termes d'une interaction mbomere entre substituant en para et le centre rdactionnel. Quoique cette explication semble justifib, il est montrk que ces faits peuvent tout aussi bien provenir d'un leger changement dans le mkhanisme de la rdaction pour les differents termes de la drie de rhctions.La constante de Hammett du groupernent para-cyclohexyl a dtd ddterminie par titration potentiometrique, et est egale -0,lS k 0,03 unites sigma.

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Substitution of Polynuclear Aromatic Compounds. I. The Friedel-Crafts Benzoylation of Naphthalene

Cited by 14 publications

References 0 publications

Validation of a Computational Model for Predicting the Site for Electrophilic Substitution in Aromatic Systems

Validation of a Computational Model for Predicting the Site for Electrophilic Substitution in Aromatic Systems

Baddeley Isomerization

The Friedel‐crafts acylation reaction. II. A study of the Hammett relationship in the Friedel‐crafts benzoylation of toluene with substituted benzoyl chlorides.

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