ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Fluoro Analoga of Cycloheptadiene Pheromones of Marine Brown Algae: Exceptionally Facile [3,3]-Sigmatropic Rearrangement of a trans-Di(alkenyl)-Substituted Geminal DifluorocyclopropaneThe 3,3,-difluorocyclopropane-1,2-dicarbonyl compounds 9a and 9b are obtained by addition of difluorocarbene to methyl cinnamate or trans-stilbene followed by oxidative degradation of the phenyl rings(s) (Scheme 2). Compound 9b is a versatile building block for the synthesis of the di(alkenyl)-substituted geminal difluorocyclopropane 5 or the chrysanthemum ester 10b. Cyclopropane 5 is unstable at room temperature and rearranges to the 3,3,-difluorocyclohepta-1,4-diene 4, an analog of the algal pheromone dictyotene (1; Scheme 3). The kinetic parameters of the [3,3]-sigmatropic rearrangement are determined. The data support the view that a geminal difluoro group within a cyclopropane weakens the distal bond.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19920750313
