Synthesis and 1H NMR Spectral Behavior of a Methano[20]annulenedione Derivative

Intramolecular oxidative coupling of 1 -(3-oxopent-1 -en-4-ynyl) -6-(1 -oxoprop-2-yny1)cyclohepta-1.3,5-triene 2 under the Glaser conditions unexpectedly afforded two tricyclic annulenediones. The unusual structures were determined b y X-ray crystallographic analysis of the compounds. These annulenediones are atropic in CDCI,, but exhibited diatropicity in CF,CO,D and D,SO, ascribable t o the formation of cationic 1 On-electron species.We have recently reported that in attempted cyclization of a series of diketones 1-9 carrying terminal acetylene groups under the Glaser conditions compounds 3, 5 and 7 gave, unexpectedly, the annulenediones 10, 11 and 12, respectively, containing a 1,4-dichIorobutatriene moiety. We showed that these annulenediones 10-12 exhibited strong diatropicity in D,SO, due to dicationic 14n-, 18n-and 22n-electron species respectively.Thus, the Glaser cyclization of compounds 1-9 succeeded when the side-chains at the 1 and 6 positions of the cycloheptatriene ring were of the same length except for the shortest and the longest members examined, 1 and 9, while 0 V O ~. 2, pp. 243-282. Structure Corporation (1 985).

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Synthesis and 1H NMR Spectral Behavior of a Methano[20]annulenedione Derivative

Abstract: A potential 18π-electron system, 11,16-dimethyl-12,14-bisdehydro-1,6-methano[20]annulene-7,20-dione was synthesized and its 1H NMR spectral behavior in CDCl3, CF3CO2D, and D2SO4 was studied. The energy barrier to the methylene flipping was highly dependent on the medium.

Cited by 2 publications

References 2 publications

The syntheses of large-ring compounds

The syntheses of large-ring compounds

Unusual formation of tricyclic annulenediones: diatropic cationic 10π-electron species in D₂SO₄

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Synthesis and 1H NMR Spectral Behavior of a Methano[20]annulenedione Derivative

Abstract: A potential 18π-electron system, 11,16-dimethyl-12,14-bisdehydro-1,6-methano[20]annulene-7,20-dione was synthesized and its 1H NMR spectral behavior in CDCl3, CF3CO2D, and D2SO4 was studied. The energy barrier to the methylene flipping was highly dependent on the medium.

Cited by 2 publications

References 2 publications

The syntheses of large-ring compounds

The syntheses of large-ring compounds

Unusual formation of tricyclic annulenediones: diatropic cationic 10π-electron species in D2SO4

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Product

Resources

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Unusual formation of tricyclic annulenediones: diatropic cationic 10π-electron species in D₂SO₄