2,4,4-Trimethylpentenyl anions

Hunter, D. H.; Mair, R. W.

doi:10.1139/v69-387

Cited by 4 publications

(1 citation statement)

References 11 publications

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“…The results were fit to a scheme which allowed for the isotope effect and the further reaction of exchanged 3. The technique is essentially that employed in an earlier study (18) and will not be described further. A ratio of 0.3 t 0.1 for k-,/k-, fit the data best and proved to be insensitive to isotope effect.…”

Section: P H H Hmentioning

confidence: 99%

2,4-Diazapentadienes. II. A Carbanion Cyclization

Hunter¹,

Sim²

1972

Can. J. Chem.

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The mechanism of thecyclization and I ,3-proton shift of 1,3,5-triaryl-2,4-diaza-I ,3-pentadienes (1) catalyzed by phenyllithium and by potassium methoxide-methanol has been studied. On the basis of substituent effects, hydrogen-deuterium exchange, isotope effects, and solvent effects, it was deduced that both thecyclization and prototropy involve a common W-shaped carbanion which rapidly cyclizes. A kinetic deuterium isotope effect of 2 was calculated for protonation of this intermediate carbanion in methanol.On ttudie le mecanisme de cyclisation et de migration-1,3 de proton dans les triaryl-1,3,5 diaza-2,4 pentaditnes-1,3 ( I ) catalystes par le phtnyllithium et par le mkthylate de potassium-methanol. En se fondant sur les effets des substituants, de I'echange hydrogtne-deutkrium, des effets isotopiques et des effets de solvant, il en a &ti. conclu que la cyclisation ainsi que la prototropie impliquent un carbanion commun en forme de W qui se cyclise rapidement. Un effet isotopique cinttique du deuterium d'unevaleur de 2 a tte calculk pour la protonation dans le methanol de ce carbanion intermediaire.

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Section: P H H Hmentioning

confidence: 99%

2,4-Diazapentadienes. II. A Carbanion Cyclization

Hunter¹,

Sim²

1972

Can. J. Chem.

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(E,Z) Equilibria, 12. Differential NMR Shielding by Phenyl, Assigned from Chemical Labelling and (Z,E) Equilibration

Knorr¹,

Hintermeyer-Hilpert²,

Böhrer³

1990

Chem. Ber.

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Unequivocal NMR assignments of the (E,Z) isomeric pairs 3 and 8 are possible by (Z,E) equilibration. Deprotonation of 2-methyl-l-phenylpropene (1) with n-BuLi under any conditions gives only a single allyl-metal derivative 2. Methylation of the latter gives the isomer (2)-3, while deuteriolysis leads to the isotopically labelled derivative 6 of the olefin 1; this proves the NMR assignments for 1 as well as the endo configuration of 2. The phenyl group gives rise to a differential shielding effect on the y-carbon nuclei in methyl and rnethylene groups along a CC double bond (ca. 7 ppm), and this effect is comparable to that along a CN double bond as in 8. The nitrile function in 5c is much less effective.

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Isomerization of Olefins

Pines

1977

Base-Catalyzed Reactions of Hydrocarbons and Related Compounds

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2,4,4-Trimethylpentenyl anions

Cited by 4 publications

References 11 publications

2,4-Diazapentadienes. II. A Carbanion Cyclization

2,4-Diazapentadienes. II. A Carbanion Cyclization

(E,Z) Equilibria, 12. Differential NMR Shielding by Phenyl, Assigned from Chemical Labelling and (Z,E) Equilibration

Isomerization of Olefins

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