1,2,3,4-Tetramethylcyclooctatetraene and 1,2,3,8-tetramethylcyclooctatetraene. Stable [8]annulene bond shift isomers

Paquette, Leo A.; Photis, James M.; Ewing, Gary D.

doi:10.1021/ja00845a054

Cited by 36 publications

(11 citation statements)

References 5 publications

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“…following the condensation of 1,2,3,4-and 1.2,3,8-tetramethylcyclooctatetraenes with N-phenyltriazolinedione 693 ; similar isomeric adducts of the dimethylcyclooctatetraene derivatives were also oxidized with manganese dioxide. 694 A synthesis of the natural product eburnamonine involves a manganese dioxide oxidation. 695 Characterization of a Mn(lV) oxide-reductase system in a marine bacillus has been attempted.…”

Section: Phosphorous Compoundsmentioning

confidence: 99%

“…e.g .• a conversion of the aldehyde 692 into the methyl ester 693 (see Section 3.10.2). Almost all oxidizing agents cyclize benzylidene-I-l'-bis-(2-naphthol) (694) to the stereoisomers 695 A mixture of 2-(hydroxymethyl)chromone (18, 2 g, 11.4 mmol) suspended in chloroform (200 ml) is refluxed with stirring for 24 h. After 12 h, an additional 2 g of manganese dioxide is added. The mixture is cooled, filtered, and the filtrate evaporated.…”

Section: M~o~mentioning

confidence: 99%

“…313 A series of secondary alcohols, e.g., 295, have been successfully oxidized to the corresponding ketones 296 with active Mn02 in tetrahydrofuran; this constitutes a convenient synthesis of thioxanthones having two heteroaromatic rings. 744 (303) was oxidized with freshly prepared active manganese dioxide in ether resulting in the ketone 306.…”

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confidence: 99%

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The Oxidation of Organic Compounds by Active Manganese Dioxide

Fatiadi

1986

Organic Syntheses by Oxidation With Metal Compounds

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Section: Phosphorous Compoundsmentioning

confidence: 99%

Section: M~o~mentioning

confidence: 99%

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The Oxidation of Organic Compounds by Active Manganese Dioxide

Fatiadi

1986

Organic Syntheses by Oxidation With Metal Compounds

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“…At the experimental level, heating of 1 with Mo(CO)e (0.1 mol equiv) in benzene at 80°for 24-48 hr gave in quantitative yield three products, the mixture consisting of ca. 40% 5, 36% 6, and 24% 7.7 Direct treatment with excess /V-phenyltriazolinedione (PTAD) in refluxing ethyl acetate resulted in formation of two adducts, hydrocarbon 7 not being subject to cycloaddition under these conditions.8 Fractional crystallization from ethyl acetate-hexane resulted in separation of the less soluble 9 mp 195-196°; NMR (CDC13) 7.2-7.55 (m, 5), 6.04 (d, J = 7 Hz, 2), 4.98 (br q, J « 7 Hz, 1), 3.10 (v br d, 1), 2.5 (br m, 1), 1.0-2.3 (m, 7), 1.67 and 1.48 (t, J =1.5 Hz, 3 each)) from 8 (mp 207-207.5°; NMR (CDC13) 7.25-7.65 (m, 5), 6.25 (m, 2), 4.70 (m, 2), 1.2-2.3 (m, 8), 1.42 and 1.25 (s, 3 each)). The emergent patterns reveal 8 to have two bridgehead protons adjoining nitrogen and a pair of olefinic protons; for 9, the most revealing features are the signals due to lone bridgehead and allylic hydrogens and the appreciable downfield shifting observed for one methylene proton.…”

Section: T H I S C O N T E N T Imentioning

confidence: 99%

Transition metal catalyzed rearrangement of 11,12-dimethyl[4.4.2]propella-2,4,11-triene as a route to stable cyclooctatetraene bond shift isomers. Implications for [1,5]-sigmatropic migration within the metal coordination sphere

Paquette¹,

Photis²,

Gifkins³

et al. 1975

J. Am. Chem. Soc.

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“…and SCF MO calculations (37) predict to be unstable. Planar cyclooctatetraene is a transition state for ring inversion (38,39) and bond shift isomerization (39,40,41) of cycloocta tetraene itself. The bond alternating planar transition state for ring inversion is of approximately 2 kcal less energy than the equal bond length transition state for bond shift isomerism.…”

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confidence: 99%

Electron spin resonance studies of the valence isomerism of 1,4- semidiones

Tanger

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The first derivative esr spectrum of 29 bicyclo[4.2,0]octa-7-ene-2j5-semidione (1) in DMSO. 2. The first derivative esr spectrum of 32 bicyclo[4.2.0]octa-3,7-diene-2,5-dione (4o) in basic dg-DMSO after 10 minutes. 3. The first derivative esr spectrum of semi-34 quinone 6^ obtained by treating semidione 1 with air. 4. The first derivative esr spectrum recorded 36 after photolysis of a solution of semidione 1 in the esr cavity. 5. The first derivative esr spectrum (top) 42 obtained from bicyclo[4.2.0]octa-7-ene-2,5-dione (_^) in dg-DMSO; calculated spectrum (bottom) for Lorentzian line width 0.115 gauss with splitting constants from text. 6. The first derivative esr spectrum (top) of 44 semidione 69; calculated spectrum (bottom) for Lorentzian line width 0.100 gauss with splitting constants from text. 7. The first derivative esr spectrum (top) of 46 4la in basic DMSO; calculated spectrum (bottom) for Lorentzian line width 0.l4 10. The first derivative esr spectrum (top) of 59 semidione 72a; the first derivative esr spectrum (middle) of semiquinone 73a; the calculated spectrum (bottom) of semiquinone 73a for Lorentzian line width 0.25 gauss with splitting constants from Table 4. 11. The first derivative esr spectrum (top) of 6l semiquinone 73c; calculated spectrum (bottom) for Lorentzian line width 0.19 gauss with splitting constants from Table 4. 12. The first derivative esr spectrum (top) of. 63 semidione 72d; calculated spectrum (bottom) for Lorentzian line width 0.25 gauss with splitting constants from Table 4. 13. The first derivative esr spectrum (top) of 65 semiquinone 73d; calculated spectrum (bottom) for Lorentzian line width O.9O gauss with splitting constants from Table 4. 14. The first derivative esr spectrum (top) of 67 semiquinone 74e; calculated spectrum (bottom) for Lorentzian line width 0.20 gauss with splitting constants from Table 4. 15. The first derivative esr spectrum (top) of 70 semiquinone 77.; calculated spectrum (bottom) for Lorentzian line width 0.14 gauss with splitting constants from text. 16. The first derivative esr spectrum (top) of 75 semidione calculated spectrum (bottom) for Lorentzian line width O.I8 gauss with splitting constants in text. 17. The first derivative esr spectrum (top) of 78 radicals observed upon greater reduction of semidione 8I; the first derivative esr spectrum (bottom) of 2,3-dimethylsemiquinone (82). 18. The first derivative esr spectrum obtained 87 by treatment of 2,4-cyclooctadiene-l,6dione (84) with potassium t-butoxide in DMSO. vi Page 19. The first derivative esr spectrum obtained 89 from 2,4-cyclooctadiene-l,6-dione in basic DMSO under flow conditions. 20. The first derivative esr spectrum obtained 97 upon treatment of acetoxy ketone 106 with basic DMSO and traces of oxygen. 21. The first derivative esr spectrum obtained 104 by treating crude diepoxide T12 with base and DMSO under flow conditions. 22. The first derivative esr spectrum obtained 110 upon treatment of 2-cyclooctene-l,4-dione CII6) with basic DMSO. 23. Esr cell used for KOtBu/DMSO experiments...

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1,2,3,4-Tetramethylcyclooctatetraene and 1,2,3,8-tetramethylcyclooctatetraene. Stable [8]annulene bond shift isomers

Cited by 36 publications

References 5 publications

The Oxidation of Organic Compounds by Active Manganese Dioxide

The Oxidation of Organic Compounds by Active Manganese Dioxide

Transition metal catalyzed rearrangement of 11,12-dimethyl[4.4.2]propella-2,4,11-triene as a route to stable cyclooctatetraene bond shift isomers. Implications for [1,5]-sigmatropic migration within the metal coordination sphere

Electron spin resonance studies of the valence isomerism of 1,4- semidiones

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