Konstante Selektivitätsbeziehungen bei Additionsreaktionen von Carbanionen

Lucius, Roland; Mayr, Herbert

doi:10.1002/1521-3757(20000602)112:11<2086::aid-ange2086>3.0.co;2-t

Cited by 34 publications

(16 citation statements)

References 29 publications

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“…Nowadays hundreds of correlations displaying constant selectivity are known, [31] and an example from our own laboratory is shown in Figure 5: [32][33][34] The 1-nitroethyl anion, the most reactive carbanion of the series shown, differentiates between a series of quinone methides in the same way as the much less nucleophilic carbanion obtained from dimedone.…”

Section: Experimental Factsmentioning

confidence: 99%

The Reactivity–Selectivity Principle: An Imperishable Myth in Organic Chemistry

Mayr¹,

Ofial²

2006

Angew Chem Int Ed

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The reactivity-selectivity principle (RSP), once a tenet of organic chemistry, eroded during the 1970s and was more or less abandoned by 1980. Although it has been clear for more than 25 years that a decrease in selectivity with increasing reactivity can only be expected with certainty if diffusion control is approached, the RSP has survived as an intuitively appealing rule. This Minireview shows why selectivity cannot generally decrease with increasing reactivity and highlights the weaknesses of the theoretical foundations of the RSP.

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Section: Experimental Factsmentioning

confidence: 99%

The Reactivity–Selectivity Principle: An Imperishable Myth in Organic Chemistry

Mayr¹,

Ofial²

2006

Angew Chem Int Ed

Self Cite

156

146

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“…[1] In previous work, we studied the nucleophilic reactivities of different types of carbanions [2] and found that pK aH values are not a reliable measure for their relative reactivities. [1] In previous work, we studied the nucleophilic reactivities of different types of carbanions [2] and found that pK aH values are not a reliable measure for their relative reactivities.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Ion‐Pairing Effects on the Nucleophilic Reactivities of Benzoyl‐ and Phenyl‐Substituted Carbanions in Dimethylsulfoxide

Corral-Bautista

Appel

Frickel

et al. 2014

Chemistry A European J

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Second-order rate constants for the reactions of acceptor-substituted phenacyl (PhCOCH(-) Acc) and benzyl anions (PhCH(-) Acc) with diarylcarbenium ions and quinone methides (reference electrophiles) have been determined in dimethylsulfoxide (DMSO) solution at 20 °C. By studying the kinetics in the presence of variable concentrations of potassium, sodium and lithium salts (up to 10(-2) mol L(-1) ), the influence of ion-pairing on the reaction rates was examined. As the concentration of K(+) did not have any influence on the rate constants at carbanion concentrations in the range of 10(-4) -10(-3) mol L(-1) , the acquired rate constants could be assigned to the reactivities of the free carbanions. The counter ion effects increase, however, in the series K(+)

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“…The impact of this so-called constant selectivity relationship has significantly been augmented by the work of Kane-Maguire and Sweigart et al who showed that Equation (2) holds also for the reactions of cationic metal p-complexes with a variety of nucleophiles. [8,9] The most extensive nucleophilicity scale, [10,11] presently available, has been derived from the rate constants of the reactions of benzhydrylium ions with alkenes, arenes, enol ethers, ketene acetals, [12] enamines, [13] allyl element compounds, [14] transition-metal p-complexes, [15] diazoalkanes, [16] and delocalized carbanions [17][18][19] (p-nucleophiles), amines, [20] alcohols, [21] alkoxides, [22] phosphanes, [23] inorganic anions [24][25][26][27] (n-nucleophiles), and a variety of hydrides [28][29][30][31] (s-nucleophiles); these rate constants were subjected to a least-squares minimization on the basis of Equation (3) [10,11] in which k is the second-order rate constant at 20 8C and E is a nucleophileindependent electrophilicity parameter.…”

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confidence: 99%