The SN2-SN1 spectrum. 2. Quantitative treatments of nucleophilic solvent assistance. A scale of solvent nucleophilicities

Schadt, Frank L.; Bentley, T. William; Schleyer, Paul von Ragué

doi:10.1021/ja00440a037

Cited by 348 publications

(213 citation statements)

References 2 publications

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“…5 More recently, NT scales based on the solvolyses of the S-methyldibenzothiophenium ion (MeDBTh + ) 6,7 have been developed, in which the leaving group is a neutral molecule, which is little influenced by solvent change. The N T values have been become the recognized standards for considerations of solvent nucleophilicity.…”

Section: Introductionmentioning

confidence: 99%

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Lee¹,

Seong²,

Kyong³

et al. 2010

Bulletin of the Korean Chemical Society

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The specific rates of solvolysis of t-butyl fluoroformate (1) have been measured at 40.0 o C in 21 pure and binary solvents. These give a satisfactory correlation over the full range of solvents when the extended Grunwald-Winstein equation, with incorporation of the solvent nucleophilicity and the solvent ionizing power, is applied. The actual values are very similar to those obtained in earlier studies of the solvolyses of isopropyl chloroformate and ethyl chlorothioformate in the more ionizing and least nucleophilic solvents, which are believed to proceed by an ionization pathway. The small negative values for the entropies of activation are consistent with the ionization nature of the proposed rate-determining step. These observations are also compared with those previously reported for the corresponding primary and secondary alkyl haloformate esters.

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Section: Introductionmentioning

confidence: 99%

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Lee¹,

Seong²,

Kyong³

et al. 2010

Bulletin of the Korean Chemical Society

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“…The extended Grunwald-Winstein equation (eqn 1) [1][2][3][4] is very useful for the correlation of solvolysis reactions: log(k/k 0 ) RX …”

Section: Introductionmentioning

confidence: 99%

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Chloroformate

Kyong

Won

Kevill

2005

IJMS

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Application of the extended Grunwald-Winstein equation to solvolyses of n-propyl chloroformate in a variety of pure and binary solvents indicates an addition-elimination pathway in the majority of the solvents but an ionization pathway in the solvents of highest ionizing power and lowest nucleophilicity. For methanolysis, a solvent deuterium isotope effect of 2.17 is compatible with the incorporation of general-base catalysis into the substitution process. Activation parameters are consistent with the duality of mechanism. Very modest positive salt effects are observed on adding chloride or bromide salts to the ethanolysis.

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“…First of all, it is seen that the extent of scrambling for a given cation generated from reaction in TFE-2,6-lutidine or CF3COOH-CF3COOAg is much greater than the corresponding scrambling for the same cation generated from reaction in HOAc-AgOAc. This is not surprising since in solvents of low nucleophilic character, such as TFE or trifluoroacetic acid (TFA) (22), the cation would have a longer lifetime, thus allowing for more 1,2-shifts and giving rise to a greater amount of scrambling. For a given set of cations that differ only in the migrating aryl group, with the aryl groups at the migration origin and migration terminus remaining the same, such as cations l , 2 , and 3 , 4 , 5 , and 6, or 7 , 8 , and 9, an increasing extent of scrambling follows the order of increasing migratory aptitude, i.e., the order in the extent of scrambling is 3 > 2 > 1, 6 > 5 > 4, and 9 > 8 > 7, in accord with the expected order of migratory aptitude of An > To1 > Ph.…”

Section: Resultsmentioning

confidence: 99%

Solvolytic rearrangement studies with (E)- and (Z)-2-anisyl-1,2-ditolyl[2-¹³C]vinyl bromides

Lee¹,

Wanigasekera²

1987

Can. J. Chem.

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Reaction of (E,Z)-or (E)-2-anisyl-1,2-ditolyl[2-13C]vinyl bromides ((E,Z)- or (E)-6-Br-2-13C) with HOAc–AgOAc gave a 1:1 mixture of (E)- and (Z)-2-anisyl-1,2-ditolyl[1,2-13C]vinyl acetates ((E,Z)-6-OAc-1,2-13C), with about 37.4% scrambling of the label from C-2 to C-1 arising from degenerate 1,2-anisyl shifts in the 2-anisyl-1,2-ditolyl[2-13C]vinyl cation (6-2-13C). No detectable amount of 1-anisyl-2,2-ditolylvinyl acetate was formed, indicating no nondegenerate 1,2-tolyl shift in cation 6 to give the more stable 1 -anisyl-2,2-ditolylvinyl cation (10) in the reaction with HOAc–AgOAc. Reaction of (E)-6-Br-2-13C with 2,2,2-trifluoroethanol (TFE) in the presence of 2,6-lutidine gave as major product 1-anisyl-2,2-ditolyl[1,2-13C]vinyl 2,2,2-trifluoroethyl ether (10-OTFE-1,2-13C) and a 1:1 mixture of (E)- and (Z)-2-anisyl-1,2-ditolyl[1,2-13C]vinyl 2,2,2-trifluoroethyl ethers ((E,Z)-6-OTFE-1,2-13C) as minor products, the ratio of 10-OTFE to (E,Z)-6-OTFE being about 80:20. Scrambling on the 13C label in the major product, 10-OTFE-1,2-13C, was 48.8 ± 0.9% and scrambling in the minor products, (E,Z)-6-OTFE-1,2-13C, was 47.2 ± 1.4%. The present work with cation 6 completes the series of nine possible triarylvinyl cations, with various combinations of phenyl (Ph), p-tolyl (Tol), and (or) p-anisyl (An) as the three aryl groups, that can give rise to degenerate 1,2-aryl shifts across the double bond, and the present results are discussed in conjunction with data from previous work on the other eight triarylvinyl cationic systems.

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The SN2-SN1 spectrum. 2. Quantitative treatments of nucleophilic solvent assistance. A scale of solvent nucleophilicities

Cited by 348 publications

References 2 publications

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Chloroformate

Solvolytic rearrangement studies with (E)- and (Z)-2-anisyl-1,2-ditolyl[2-¹³C]vinyl bromides

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The SN2-SN1 spectrum. 2. Quantitative treatments of nucleophilic solvent assistance. A scale of solvent nucleophilicities

Cited by 348 publications

References 2 publications

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Chloroformate

Solvolytic rearrangement studies with (E)- and (Z)-2-anisyl-1,2-ditolyl[2-13C]vinyl bromides

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Solvolytic rearrangement studies with (E)- and (Z)-2-anisyl-1,2-ditolyl[2-¹³C]vinyl bromides