The SRN1 Reaction: An Attempt to Calculate the Thermodynamic Driving Force for the Addition of Nucleophiles to Phenyl Radical.

Galli, Carlo; Gentili, Patrizia; Wagenknecht, J. H.; Francis, George W.; Szúnyog, József; Långström, Bengt

doi:10.3891/acta.chem.scand.52-0067

Cited by 19 publications

(38 citation statements)

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“…The corresponding values from the aromatic homologues (i.e., PhϪY) are given in parentheses. [22] [d] From kcal/mol for Ph · , [30] and the reasonable agreement with these data supports the reliability of our semiempirical calculations. In combination with the ∆H°f value of H · (52.1 kcal/ mol), [31] the data in Table 4 enable the involved BDE CϪH values to be calculated.…”

Section: Semiempirical Calculationssupporting

confidence: 81%

“…[12] This confirms that aryl radicals are both thermodynamically and kinetically efficient in their reaction with the enolate ions, with rate constants approaching the diffusion limit (ca. 10 11  Ϫ1 ·s Ϫ1 ) [22] in these solvents.…”

Section: Competition Between Nucleophilic Attack and H-atom Abstractimentioning

confidence: 88%

“…Available experimental data are 71.7 kcal/mol for CH 2 ϭCH · , [29] and 81.1 [a] Taken from ref. [22] [b] Calculated from Benson's group increments. [22] [c] BDE CϪY ϭ ∆H°f(CH 2 ϭC{ · }Ph) ϩ ∆H°f(Y · ) Ϫ ∆H°f(CH 2 ϭ C{Ph}Y); ∆H°f(CH 2 ϭC{ · }Ph) ϭ 70 kcal/mol (from Table 4, the α-Ph is Ќ).…”

Section: Semiempirical Calculationsmentioning

confidence: 99%

“…[22] [b] Calculated from Benson's group increments. [22] [c] BDE CϪY ϭ ∆H°f(CH 2 ϭC{ · }Ph) ϩ ∆H°f(Y · ) Ϫ ∆H°f(CH 2 ϭ C{Ph}Y); ∆H°f(CH 2 ϭC{ · }Ph) ϭ 70 kcal/mol (from Table 4, the α-Ph is Ќ). The corresponding values from the aromatic homologues (i.e., PhϪY) are given in parentheses.…”

Section: Semiempirical Calculationsmentioning

confidence: 99%

“…In combination with the ∆H°f value of H · (52.1 kcal/ mol), [31] the data in Table 4 enable the involved BDE CϪH values to be calculated. [22] The lower value of BDE CϪH (ca. 8 kcal/mol) corresponding to the Ќ α-Ph-substituted H 2 Cϭ C( · )Ph, in comparison both with the // α-Ph-substituted H 2 CϭC( · )Ph and also with PhCHϭCH · , in which delocalization of the odd electron on the phenyl substituent is prevented, supports a stabilization of the Ќ α-Ph-substituted vinyl radical.…”

Section: Semiempirical Calculationsmentioning

confidence: 99%

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Reactivity of Aryl and Vinyl Radicals: Abstraction of Hydrogen Atom or Reaction with a Nucleophile

2002

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Section: Semiempirical Calculationssupporting

confidence: 81%

Section: Competition Between Nucleophilic Attack and H-atom Abstractimentioning

confidence: 88%

Section: Semiempirical Calculationsmentioning

confidence: 99%

Section: Semiempirical Calculationsmentioning

confidence: 99%

Section: Semiempirical Calculationsmentioning

confidence: 99%

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Reactivity of Aryl and Vinyl Radicals: Abstraction of Hydrogen Atom or Reaction with a Nucleophile

2002

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A Radical and An Electron Transfer Process Are Compared in Their Regioselectivities Towards A Molecule with Two Different C−I Bonds: Effect of Steric Congestion

et al. 2000

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Steric compression in 1,4-diiodo-2,6-dimethylbenzene (2a) makes the C−I bond flanked by methyls substantially weaker (a buttressing effect) than the unhindered C−I bond. Calculations also confirm the weaker bonding interaction of the hindered C−I bond of 2a. This causes a remarkable regioselectivity toward the weaker bond in dehalogenation by stannyl radicals. Conversely, a much lower regioselectivity is found for a process −a photostimulated S RN 1 reaction with [a] 2663 the enolate ion of a ketone − which requires the conversion of 2a into a radical anion. A calculation of the BDE of the C−I bond for aa ArI •− system is offered. Finally, the hindered aryl radical intermediate resulting from cleavage of the weaker C−I bond of 2a •− shows a modest but detectable discrimination between reduction or substitution, this once again being due to the steric congestion.

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Determination of Rate Constants for the Reaction of Aryl Radicals with Enolate Ions

et al. 2001

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The rate of ring closure (k C ) of o-(ω-alkenyl)aryl radicals by means of an intramolecular attack of the intermediate phenyl-type radical at the tethered double bond was found to be 4.2 × 10 8 s −1 (for 1 • ) and 7.6×10 7 s −1 (for 8 • ), both being 6-exo-trig processes, and 9.6 × 10 9 s −1 for the 5-exo-trig process of 3 • . The k C rate constant of these radicals was calibrated with respect to a known rate of H-atom abstraction (k H ). The photostimulated S RN 1 reactions of radical clock precursor 1 with anions PhS − and (EtO) 2 PO − in Me 2 SO at 25°C provided the rates of addition of these nucleophiles (k Y ) to intermediate 1 • (3.2 × 10 8 and 2.5 × 10 9 M −1 s −1 , respect-

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The SRN1 Reaction: An Attempt to Calculate the Thermodynamic Driving Force for the Addition of Nucleophiles to Phenyl Radical.

Cited by 19 publications

References 0 publications

Reactivity of Aryl and Vinyl Radicals: Abstraction of Hydrogen Atom or Reaction with a Nucleophile

Reactivity of Aryl and Vinyl Radicals: Abstraction of Hydrogen Atom or Reaction with a Nucleophile

A Radical and An Electron Transfer Process Are Compared in Their Regioselectivities Towards A Molecule with Two Different C−I Bonds: Effect of Steric Congestion

Determination of Rate Constants for the Reaction of Aryl Radicals with Enolate Ions

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