Experimental and Calculated Electrochemical Potentials of Common Organic Molecules for Applications to Single-Electron Redox Chemistry

Roth, Hudson G.; Romero, Nathan A.; Nicewicz, David A.

doi:10.1055/s-0035-1561297

Cited by 447 publications

(226 citation statements)

References 34 publications

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“…14 A focused microscale (10 μmol) high-throughput-screen (HTS) was performed for the study of arylation of ketimine 1a with 4- tert -butyliodobenzene ( 2a ) at room temperature for 6 h. Other parameters included six solvents (THF, CPME, DME, MTBE, toluene, and cyclohexane), two bases [LiN(SiMe 3 ) 2 and NaN(SiMe 3 ) 2 ] and two concentrations (0.1 M and 0.2 M). The best conditions in this screen involved DME, NaN(SiMe 3 ) 2 at 0.2 M concentration.…”

Section: Resultsmentioning

confidence: 99%

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Transition-Metal-Free Radical C(sp³)–C(sp²) and C(sp³)–C(sp³) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Berritt

Matuszewski

et al. 2017

J. Am. Chem. Soc.

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The past decade has witnessed the rapid development of radical generation strategies and their applications in C–C bond-forming reactions. Most of these processes require initiators, transition metal catalysts or organometallic reagents. Herein, we report the discovery of a simple organic system (2-azaallyl anions) that enables radical coupling reactions under transition-metal-free conditions. Deprotonation of N-benzyl ketimines generates semi-stabilized 2-azaallyl anions that behave as “super-electron-donors” (SEDs) and reduce aryl iodides and alkyl halides to aryl and alkyl radicals. The SET process converts the 2-azaallyl anions into persistent 2-azaallyl radicals, which capture the aryl and alkyl radicals to form C–C bonds. The radical coupling of aryl and alkyl radicals with 2-azaallyl radicals makes possible the synthesis of functionalized amine derivatives without the use of exogenous radical initiators or transition metal catalysts. Radical clock studies and 2-azaallyl anion coupling studies provide mechanistic insight for this unique reactivity.

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Section: Resultsmentioning

confidence: 99%

“…14 We selected neopentyl iodide ( 3a ) as the model alkylation electrophile because its steric hindrance precludes an S N 2 coupling pathway. 10 The same parameters employed in Scheme 3a were applied to the 10 μmol scale screening of ketimine 1a with neopentyl iodide ( 3a ; rt for 6 h, Scheme 4a).…”

Section: Resultsmentioning

confidence: 99%

Transition-Metal-Free Radical C(sp³)–C(sp²) and C(sp³)–C(sp³) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Berritt

Matuszewski

et al. 2017

J. Am. Chem. Soc.

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“…1 Unactivated methylene and methine systems, the most ubiquitous structural motifs in organic chemistry, have high redox potentials (oftentimes above 3.0 V vs SCE, see Figure 1A). 2,3 Thus, under direct electrolysis, oxidative degradation of other functionalities and solvents is likely to occur prior to the desired C–H oxidation. 4 Instead, chemists are generally beholden to strong oxidants, such as methyl(trifluoromethyl)dioxirane (TFDO), 5,6 and metal complexes 7,8 to effect such transformations.…”

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confidence: 99%

Scalable, Electrochemical Oxidation of Unactivated C–H Bonds

et al. 2017

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A practical electrochemical oxidation of unactivated C–H bonds is presented. This reaction utilizes a simple redox mediator, quinuclidine, with inexpensive carbon and nickel electrodes to selectively functionalize “deep-seated” methylene and methine moieties. The process exhibits a broad scope and good functional group compatibility. The scalability, as illustrated by a 50 g scale oxidation of sclareolide, bodes well for immediate and widespread adoption.

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“…A similar deviation in the y-intercept was found in a recent work employing B3LYP and M06-2X for the calculation of oxidation and reduction potentials. 66 To search for an explanation of the differences obtained in the y-intercept (due to a systematic bias in the ‫ܧ‬ ோௗ ) 10…”

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confidence: 99%

In search of the best DFT functional for dealing with organic anionic species

Borioni

Puiatti

Vera

et al. 2017

Phys. Chem. Chem. Phys.

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Quantum chemical computational methods are thought to have problems in dealing with unstable organic anions. This work assesses the ability of different Density Functional Theory (DFT) functionals to reproduce the electron affinity and reduction potential of organic compounds. The performance of 23 DFT functionals was evaluated by computing the negative electron affinities (from 0 eV to -3.0 eV) and reduction potentials in acetonitrile (from 0 to -2.7 V). In general, most of the hybrid GGA functionals work fine in the prediction of electron affinities, BPW91, B3PW91 and M06 being the best in each class of functionals (pure, hybrid and meta-GGA functionals, respectively). On the other hand, the ab initio post-Hartree-Fock methods, MP2 and coupled-cluster (CCSD(T)), as well as the double hybrid functionals, B2PLYP and mPW2PLYP, usually fail. For compounds with EAs lower than -1.75 eV, a method for stabilizing the anion, based on solvation with the IEFPCM model, was employed. In this case, BPW91, PBE0 and M06-HF could be the recommended option for the pure, hybrid and meta-GGA functionals, respectively. The situation improves for the evaluation and prediction of redox potentials. In this case the performance of the DFT functionals is better, in part because the solvent assists in the stabilization of the anions. Nevertheless, there is a systematic bias in the calculation of absolute redox potentials, which could be corrected by using a redox partner that helps by the cancellation of errors. In this case, the hybrid and meta-GGA functionals B3PW91, PBE0, TPSSh and M06 are also among the best for computing redox potentials with a mean absolute deviation (MAD) lower than 0.13 V.

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Experimental and Calculated Electrochemical Potentials of Common Organic Molecules for Applications to Single-Electron Redox Chemistry

Cited by 447 publications

References 34 publications

Transition-Metal-Free Radical C(sp³)–C(sp²) and C(sp³)–C(sp³) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Transition-Metal-Free Radical C(sp³)–C(sp²) and C(sp³)–C(sp³) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Scalable, Electrochemical Oxidation of Unactivated C–H Bonds

In search of the best DFT functional for dealing with organic anionic species

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Experimental and Calculated Electrochemical Potentials of Common Organic Molecules for Applications to Single-Electron Redox Chemistry

Cited by 447 publications

References 34 publications

Transition-Metal-Free Radical C(sp3)–C(sp2) and C(sp3)–C(sp3) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Transition-Metal-Free Radical C(sp3)–C(sp2) and C(sp3)–C(sp3) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Scalable, Electrochemical Oxidation of Unactivated C–H Bonds

In search of the best DFT functional for dealing with organic anionic species

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Product

Resources

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Transition-Metal-Free Radical C(sp³)–C(sp²) and C(sp³)–C(sp³) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

Transition-Metal-Free Radical C(sp³)–C(sp²) and C(sp³)–C(sp³) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners