ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Proton Resonance Spectroscopy of Unsaturated Ring Systems, XXIII. The Cope-Rearrangement of 3,4-HomotropilideneThe activation parameters of the Cope-rearrangement of 1,2,3,4,5,6,7,7′-octadeuterio-3,4-homotro-pilidene (1,2,3,4,5,6,7,7′-octadeuteriobicyclo[5.1.0]octa-2,5-diene) have been determined between -20 and + 102°C by a complete line shape analysis of the temperature dependent 1H n.m.r. spectrum. Ea = 12.6 kcal/mole, log A = 11.6, ΔH° = 12.0 kcal/mole, ΔS≠ = -7.5 e. u., and ΔG298≠ = 13.0 kcal/mole was found. The isomer with the CH2-group at the three-membered ring is more stable than the isomer with the diallylic CH2-group by 250 cal/mole. The stereo-chemistry of the Cope-rearrangement has been evaluated.
Notes:
Die Aktivierungsparameter der Cope-Umlagerung von 1,2,3,4,5,6,7,7′-Octadeuterio-3,4-homo-tropiliden (1,2,3,4,5,6,7,7′-Octadeuteriobicyclo[5.1.0]octa-2,5-dien) wurden durch komplette Linienform-Analyse des temperaturabhängigen 1H-NMR-Spektrums zwischen -20 und +102°C bestimmt. Man fand Ea = 12.6 kcal/mol, log A = 11.6, ΔH≠ = 12.0 kcal/mol, ΔS≠ = -7.5 Clausius und ΔG298≠ = 13.0 kcal/mol. Das Isomere mit der CH2-Gruppe am Cyclopropanring ist um 250 cal/mol stabiler als das Isomere mit diallylständiger CH2-Gruppe Die Stereochemie der Cope-Umlagerung wurde ermittelt.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19751081005
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