ISSN:
1572-9001
Keywords:
Tetracycloundecane
;
d 3-trishomocubane
;
tetracycloundec-4-ene
;
molecular mechanics
;
semiempirical calculations
;
X-ray analysis
;
carbonium ion rearrangements
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Reaction of 8,8,11,11-tetrafluoropentacyclo[5.4.0.02,6.03,10.05,9]undecane with idio trimethylsilane leads to the expectedd 3-trishomocubane derivative, but reaction with the more electrophilic boron tribromide yields a tetracyclo[6.3.0.02,6.03,10]undec-4-ene derivative which was characterized by X-ray diffraction. The most easily visualized pathway for this transformation would be an initial rearrangement of the starting material to ad 3-trishomocubane followed by additional bond breaking to form the undec-4-ene compound. Molecular mechanics calculations indicate the brominatedd 3-trishomocubane is about 4 kcal/mol more stable than the brominated undec-4-ene molecule and the associated carbonium ions show the same ordering. These data would indicate an alternate reaction pathway must be operative; however, semiempirical calculations predict the reverse ordering of the above energies.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02275451
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