Electrochemical reduction of (+)-(2S,4S)-2,4-dibromopentane

Fry, Albert J.; Britton, Wayne E.

doi:10.1021/jo00987a013

Cited by 38 publications

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“…Doering and Kirmse reported [α] D −46.0 (diethyleneglycol dimethyl ether, diglyme) for optically pure (−)- 2 . Subsequent measurements have given [α] D −42 (pentane) and [α] D −46 (heptane) …”

Section: Resultsmentioning

confidence: 99%

Determination of Absolute Configuration Using Density Functional Theory Calculation of Optical Rotation: Chiral Alkanes

McCann

Stephens

Cheeseman³

2004

J. Org. Chem.

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The recently developed Gauge-Invariant (Including) Atomic Orbital (GIAO) based Time-Dependent Density Functional Theory (TDDFT) methodology for the calculation of transparent spectral region optical rotations of chiral molecules provides a new approach to the determination of absolute configurations. Here, we discuss the application of the TDDFT/GIAO methodology to chiral alkanes. We report B3LYP/aug-cc-pVDZ calculations of the specific rotations of the 22 chiral alkanes, 2-23, of well-established Absolute Configuration. The average absolute deviation of calculated and experimental [alpha](D) values for molecules 2-22 is 24.8. In two of the molecules 2-23, trans-pinane, 10, and endo-isocamphane, 13, the sign of [alpha](D) is incorrectly predicted. Our results demonstrate that absolute configurations of alkanes can be reliably assigned by using B3LYP/aug-cc-pVDZ TDDFT/GIAO calculations if, but only if, [alpha](D) is significantly greater than 25. In the case of (-)-anti-trans-anti-trans-anti-trans-perhydrotriphenylene, 1, [alpha](D) is -93 and TDDFT/GIAO calculations reliably lead to the absolute configuration R(-).

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Section: Resultsmentioning

confidence: 99%

Determination of Absolute Configuration Using Density Functional Theory Calculation of Optical Rotation: Chiral Alkanes

McCann

Stephens

Cheeseman³

2004

J. Org. Chem.

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“…HPLC grade CH 3 CN (Tedia) was used as received, and Bu 4 NPF 6 was prepared and purified by standard methods. 7 Water with a resistivity of no less than 18 MΩ cm was used for experiments at different pH-values. Sulfuric acid was used for experiments at pH 1.…”

Section: Methodsmentioning

confidence: 99%

Long-Lived Radical Cations as Model Compounds for the Reactive One-Electron Oxidation Product of Vitamin E

et al. 2008

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Heterocyclic compounds with structures similar to vitamin E, but without the hydroxyl hydrogen atom, were synthesized and their electrochemical behavior examined in acetonitrile solutions and as solids in aqueous solutions of varying pH by attaching the compounds to the surface of a glassy carbon electrode. Compound 1, containing a fully methylated aromatic ring was found to be the most long-lived following one-electron oxidation, with its radical cation (1 +• ) surviving in acidic aqueous solutions and able to be isolated as a salt, 1 +• (SbF 6 -), when reacted with NOSbF 6 in CH 3 CN. Electrochemical, UV-vis and FTIR experiments on 1 +• , in addition to the results from theoretical calculations, indicated that the electrochemical, electronic and structural properties of 1 +• are very similar to those of the radical cation of vitamin E.

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“…For example, both direct and mediated electrochemical reductions of 1,3-dihalopropanes at mercury, aluminum, carbon, and platinum cathodes afford cyclopropane as a major product, [1][2][3][4][5][6][7][8][9] which could be formed from either a radical or carbanion intermediate. By comparing product distributions for the direct electrochemical reductions of meso-and dl-2,4-dibromopentane in dimethyl sulfoxide containing tetraethylammonium bromide, Fry and Britton 10,11 established that cyclopropane arises via a pathway involving intramolecular cyclization of an electrogenerated halocarbanion intermediate, because cis-and trans-1,2-dimethylpropane were obtained equally from electrolyses of the two diastereomers.…”

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confidence: 99%

Catalytic Reduction of 1,6-Dihalohexanes by Nickel(I) Salen Electrogenerated at Glassy Carbon Cathodes in Dimethylformamide

Vanalabhpatana

Peters

2005

J. Electrochem. Soc.

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Reaction between stoichiometric amounts of 1,6-dihalohexanes and electrogenerated nickel͑I͒ salen in dimethylformamide containing 0.10 M tetramethylammonium tetrafluoroborate affords cyclohexane in up to 78% yield. Arising via a radical pathway, an -haloalkylnickel͑II͒ species is a proposed intermediate for these reductions in which alkanes, 1-alkenes, and aldehydes are also produced. In cyclic voltammetric studies at scan rates of 5-25 mV s −1 , formation of a passivating film on the surface of the carbon cathode has a dramatic effect on the catalytic reduction of 1,6-dihalohexanes, but this electrode fouling can be overcome by addition of acetic acid to the medium. For controlled-potential electrolyses involving the reduction of a 1,6-dihalohexane with catalytic amounts of electrogenerated nickel͑I͒ salen in the presence of excess acetic acid, most of the substrate is converted into three different esters ͑hexyl acetate, 1,6-diacetoxyhexane, and dodecyl acetate͒ which arise via nucleophilic ͑S N 2͒ attack of acetate ion on the dihaloalkane.

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Electrochemical reduction of (+)-(2S,4S)-2,4-dibromopentane

Cited by 38 publications

References 0 publications

Determination of Absolute Configuration Using Density Functional Theory Calculation of Optical Rotation: Chiral Alkanes

Determination of Absolute Configuration Using Density Functional Theory Calculation of Optical Rotation: Chiral Alkanes

Long-Lived Radical Cations as Model Compounds for the Reactive One-Electron Oxidation Product of Vitamin E

Catalytic Reduction of 1,6-Dihalohexanes by Nickel(I) Salen Electrogenerated at Glassy Carbon Cathodes in Dimethylformamide

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