Radical Ion Probes. 3. The Importance of Resonance vs. Strain Energy in the Design of SET Probes Based upon the Cyclopropylcarbinyl-to-Homoallyl Radical Rearrangement

Tanko, James M.; Drumright, Ray E.; Suleman, N. Kamrudin; Brammer, Larry E.

doi:10.1021/ja00084a020

Cited by 33 publications

(37 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this paper, results pertaining to the homogeneous CAN oxidation of several cyclopropylarenes in CH 3 CN-CH 3 OH are reported. The cyclopropane-containing substrates chosen for study include 1-cyclopropylbenzene (1), 1-cyclopropyl-4methylbenzene (2), 1-cyclopropylnaphthalene (3), 1-bromo-4cyclopropylnaphthalene (4), 2-cyclopropylnaphthalene (5), 9-cyclopropylanthracene (6) and 9-bromo-10-cyclopropylanthracene (7).…”

Section: Methodsmentioning

confidence: 99%

“…The HPLC yields of products thus obtained are summarized in Table 3 (HPLC conditions: CH 3 CN-H 2 O 9 : 1, flow rate = 1 mL min Ϫ1 , UV detector: λ = 256 nm). 9-Bromo-10-cyclopropylanthracene (7). The reaction of 9bromo-10-cyclopropylanthracene with CAN was performed by a similar procedure as that for 9-cyclopropylanthracene.…”

Section: Can Oxidation Of Cyclopropylanthracenesmentioning

confidence: 99%

See 1 more Smart Citation

Radical ion probes. Part 10. Ceric(IV) ammonium nitrate oxidation of cyclopropylarenes†

Wang¹,

Tanko²

1998

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

Section: Methodsmentioning

confidence: 99%

Section: Can Oxidation Of Cyclopropylanthracenesmentioning

confidence: 99%

Radical ion probes. Part 10. Ceric(IV) ammonium nitrate oxidation of cyclopropylarenes†

Wang¹,

Tanko²

1998

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

“…Since the electron transfer steps in all of these cases were known to be endergonic processes (i.e. the reverse reaction will be much faster than the forward), there have been a number of attempts to “calibrate” the mechanistic probes, by determining the rate constant for fragmentation of the radical anions. − The ideal mechanistic probe is one in which the rate of oxidation of the radical anion (i.e. back electron transfer) cannot compete with fragmentation.…”

Section: Introductionmentioning

confidence: 99%

Electrochemistry of Electron-Transfer Probes. The Role of the Leaving Group in the Cleavage of Radical Anions of α-Aryloxyacetophenones¹

1996

View full text Add to dashboard Cite

The formal reduction potential (E°) of α-phenoxyacetophenone has been determined from the voltammetric peak potential obtained by linear sweep voltammetry in combination with the rate constant for fragmentation of the radical anion which had been determined by laser flash photolysis. The E° values of a number of α-aryloxyacetophenones were then estimated from a correlation of the 13C chemical shifts of the carbonyl carbon and a similar correlation (E° versus 13C chemical shift) within a series of substituted α-anilinoacetophenones. Using these potentials (which vary by only 34 mV over a wide range of substituents) the rate constants for fragmentation of the α-aryloxyacetophenone radical anions were determined from digital simulation of the corresponding voltammetric waves. The fragmentation rate constants were shown to correlate with the pK a of the corresponding phenols. However, the kinetic range was too small and the experimental errors too large to allow a distinction between a linear and quadratic free energy dependence. A thermochemical analogy between the leaving group ability in reactions of radical anions and that in simple heterolysis of closed shell compounds is developed. The utility of these compounds as potential electron transfer probes is discussed.

show abstract

“…(11)], phenyl substitution on the cyclopropyl group increases the rate constant by at least six orders of magnitude. [23] The fact that k o for 5 * À and 6 * À are nearly the same provides further compelling evidence for CÀ O bond cleavage. (Note: This is further supported by the calculations summarized in Table 4.…”

Section: Cà C Cleavage [Kcal • Mol à 1 ]mentioning

confidence: 91%

Interplay between Structure and Mechanism in Reductive Dissociative Electron Transfers to α,β ‐Epoxyketones

2020

Self Cite

View full text Add to dashboard Cite

The electrochemical reduction of several α,β-epoxyketones was studied using cyclic (linear sweep) voltammetry, convolution voltammetry, and homogeneous redox catalysis. The results were reconciled to pertinent theories of electron transfer. α,β-Epoxyketones undergo dissociative electron-transfer reactions with CÀ O bond cleavage, via both stepwise and concerted mechanisms, depending on their structure. For aliphatic ketones, the preferred mechanism of reduction is consistent with the "sticky" concerted model for dissociative electron transfer. Bond cleavage occurs simultaneously with electron transfer, and there is a residual, electrostatic interaction in the ring-opened (distonic) radical anion. In contrast, for aromatic ketones, because the ring-closed radical anions are resonancestabilized and exist at energy minima, a stepwise mechanism operates (electron transfer and bond cleavage occur in discrete steps). The rate constants for ring opening are on the order of 10 8 s À 1 , and not significantly affected by substituents on the 3membered ring (consistent with CÀ O bond cleavage). These results and conclusions were fully supported and augmented by molecular orbital calculations.

show abstract

Radical Ion Probes. 3. The Importance of Resonance vs. Strain Energy in the Design of SET Probes Based upon the Cyclopropylcarbinyl-to-Homoallyl Radical Rearrangement

Cited by 33 publications

References 0 publications

Radical ion probes. Part 10. Ceric(IV) ammonium nitrate oxidation of cyclopropylarenes†

Radical ion probes. Part 10. Ceric(IV) ammonium nitrate oxidation of cyclopropylarenes†

Electrochemistry of Electron-Transfer Probes. The Role of the Leaving Group in the Cleavage of Radical Anions of α-Aryloxyacetophenones¹

Interplay between Structure and Mechanism in Reductive Dissociative Electron Transfers to α,β ‐Epoxyketones

Contact Info

Product

Resources

About

Radical Ion Probes. 3. The Importance of Resonance vs. Strain Energy in the Design of SET Probes Based upon the Cyclopropylcarbinyl-to-Homoallyl Radical Rearrangement

Cited by 33 publications

References 0 publications

Radical ion probes. Part 10. Ceric(IV) ammonium nitrate oxidation of cyclopropylarenes†

Radical ion probes. Part 10. Ceric(IV) ammonium nitrate oxidation of cyclopropylarenes†

Electrochemistry of Electron-Transfer Probes. The Role of the Leaving Group in the Cleavage of Radical Anions of α-Aryloxyacetophenones1

Interplay between Structure and Mechanism in Reductive Dissociative Electron Transfers to α,β ‐Epoxyketones

Contact Info

Product

Resources

About

Electrochemistry of Electron-Transfer Probes. The Role of the Leaving Group in the Cleavage of Radical Anions of α-Aryloxyacetophenones¹