Nucleophilic Reactivities of Imide and Amide Anions

Breugst, Martin; Tokuyasu, Takahiro; Mayr, Herbert

doi:10.1021/jo1009883

Cited by 77 publications

(65 citation statements)

References 73 publications

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“…It is noteworthy to mention that the deviations between calculated rate constants from the three parameters of Eq. (1) and experimental rate constants have also been observed by many authors but still remain difficult to rationalize [15][16][17][27][28][29][30][31][32][33].…”

Section: Log K Exp Versus Log K Calcd Relationshipmentioning

confidence: 99%

Reactions of N1-Methyl-4-nitro-2,1,3-benzoselenadiazolium Tetrafluoroborate with Aliphatic and Cyclic Amines in Acetonitrile: Kinetic and Structure-Reactivity Correlations

Salah

Boubaker

Goumont

2017

Int. J. Chem. Kinet.

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The nucleophilic addition reactions of N1‐methyl‐4‐nitro‐2,1,3‐benzoselenadiazolium tetrafluoroborate 1 with aliphatic amines 2a–c (diethylamine 2a, dipropylamine 2b, and allylamine 2c) have been kinetically studied by UV–vis spectroscopy in acetonitrile solution at 20°C. The kinetic data have been analyzed, using the Mayr equation, allowing the quantification of the electrophilicity parameter (E) value of benzoselenadiazolium cation 1 (E = −14.72). The reliability of parameter E has been reasonably verified by comparison of calculated and experimental second‐order rate constants for the reactions of cation 1 with other amines 2d–f (pyrrolidine 2d, piperidine 2e, and morpholine 2f) under the same conditions as those of the amines 2a–c. A linear Brönsted plot (R2 = 0.9945) with a βnuc value of 0.55 has been obtained for the reactions of 1 with the secondary amines employed in the present work. Interestingly, satisfactory correlation between the log values of measured and calculated rate constants with a slope very close to unity has been obtained and discussed.

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Section: Log K Exp Versus Log K Calcd Relationshipmentioning

confidence: 99%

Reactions of N1-Methyl-4-nitro-2,1,3-benzoselenadiazolium Tetrafluoroborate with Aliphatic and Cyclic Amines in Acetonitrile: Kinetic and Structure-Reactivity Correlations

Salah

Boubaker

Goumont

2017

Int. J. Chem. Kinet.

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“…The linear free energy relationship given in Eq. (1) [1][2][3], in which the electrophile is characterized by a single parameter (E) and the nucleophile is characterized by two parameters (N, s), has been applied to Scheme 1 describe quantitatively the reaction rates of a large variety of electrophile-nucleophile combinations in which nucleophilic addition is rate limiting [3][4][5][6][7][8][9][10][11][12][13][14][15]. The electrophilicity scale thus established presently covers a reactivity range of 32 orders of magnitude, from E = −23.80 for substituted diethyl benzylidenemalonate 4 [16] to E = 8.02 for the 3,5-difluoro-substitued benzhydrilium ion 5 [17].…”

Section: Introductionmentioning

confidence: 99%

Nucleophilic Substitution Reactions of 2‐Methoxy‐3‐X‐5‐nitrothiophenes: Effect of Substituents and Structure–Reactivity Correlations

Echaieb

Gabsi

Boubaker

2014

Int J of Chemical Kinetics

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A kinetic study is reported for reactions of 2‐methoxy‐3‐X‐5‐nitrothiophenes 1a–d (X = SO2CH3, CO2CH3, CONH2, H) with piperidine in different solvents at 20°C. It is shown that the reactions take place through a SNAr mechanism with the initial nucleophilic addition step being rate limiting. The satisfactory Hammett correlations (log k1 vs. σnormalp−) obtained in the present system confirms that a 3‐X substituent exerts an effect on the 2‐position of the same type as that exerted from the 5‐position. The second‐order rate constants associated with these reactions are employed to determine the electrophilicity parameters E of the thiophenes 1a–d according to the relationship log k (20°C) = s(E + N) (Angew. Chem., Int. Ed. Engl. 1994, 33, 938–957). The E values of 1a–d are found to cover a range from −21.33 to −17.18, going from 1d, the least reactive, to 1a, the most reactive thiophene. Interestingly, a linear correlation (r2 = 0.9910) between the electrophilicity parameters E determined in this work and the Hammett's σnormalp− constants values has been observed and discussed. On the other hand, we have found that the reported rate constants of some thiophenes 1 complexation by the methoxide ion in methanol are 3.5–73.5 times higher than predicted by Mayr's approach.

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“…17,18 Obviously aminooxygenation products 9 represent kinetic products. We explain the notable difference in the present catalysis by the fact that reductive elimination from the intermediary palladium(IV) catalyst state B is a fast process resulting in kinetic C-O bond formation.…”

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confidence: 99%

Regioselective Intermolecular Diamination and Aminooxygenation of Alkenes with Saccharin

et al. 2016

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Palladium catalysis enables the regioselective difunctionalization of alkenes using saccharin as the nitrogen source in the initial step of aminopalladation. Depending on the reaction conditions, diamination or aminooxygenation pathways can be accessed using hypervalent iodine reagents as the terminal oxidants. The aminooxygenation of allylic ethers originates from an unprecedented ambident behavior of saccharine. The participating palladium catalysts contain a palladium-saccharide unit. Two representative complexes of this type could be isolated and characterized.The oxidative difunctionalization of alkenes represents a powerful tool for the efficient 1,2-introduction of heteroatoms into organic framework and thus for structural diversification from common hydrocarbon groups.1 Within such vicinal difunctionalization, palladium catalysis constitutes a particularly effective approach. In this particular area, the development of conditions that are applicable to intermolecular reaction control are of particular challenge. A currently limited number of different protocols have become available including dihalogenation, 2 dioxygenation, 3 aminooxygenation, 4 aminofluorination 5 and diamination 6 reactions.Since vicinal diamines constitute an important class of functional groups that are present in a number of molecular entities of pharmaceutical and medicinal interest, 7 function as effective ligands to transition metals to provide catalysts, 8,9 the development of new avenues for their synthesis is of major interest. Within this context, the direct vicinal diamination of alkenes offers a straightforward access, 10 and we have been interested in devising suitable reaction conditions that enable palladium catalysis to operate under completely intermolecular conditions. 6,11 Some time ago, we introduced saccharin as a useful nitrogen source in the palladium-catalyzed vicinal diamination of alkenes under intermolecular reaction control. 6a The combination of this particular imine together with iodosobenzene diacetate and bissulfonylimines as a second nitrogen source enabled the realization of the first regio and chemoselective diamination of terminal alkenes. Saccharin owes its attractiveness as a nitrogen source to its commercial availability and low price.We recently investigated the composition of the active palladium catalyst in related oxidative amination reactions of alkenes with phthalimide. 12 We could demonstrate that the initial palladium dichloride or diacetate salt is readily transformed into the corresponding bisphthalimidato palladium derivatives at the outset of the reaction.We were intrigued to study the performance of these common palladium salts in the presence of saccharin 1 as well. Indeed, when an acetonitrile solution of palladium diacetate 2 is treated with 2 equivalents saccharin 1, clean formation of the new bisacetonitrile palladium disaccharide complex 3 is observed. This complex is obtained as a stable yellowish solid (Scheme 1). Attempts to crystallize this compound from organic...

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Nucleophilic Reactivities of Imide and Amide Anions

Cited by 77 publications

References 73 publications

Reactions of N1-Methyl-4-nitro-2,1,3-benzoselenadiazolium Tetrafluoroborate with Aliphatic and Cyclic Amines in Acetonitrile: Kinetic and Structure-Reactivity Correlations

Reactions of N1-Methyl-4-nitro-2,1,3-benzoselenadiazolium Tetrafluoroborate with Aliphatic and Cyclic Amines in Acetonitrile: Kinetic and Structure-Reactivity Correlations

Nucleophilic Substitution Reactions of 2‐Methoxy‐3‐X‐5‐nitrothiophenes: Effect of Substituents and Structure–Reactivity Correlations

Regioselective Intermolecular Diamination and Aminooxygenation of Alkenes with Saccharin

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