ISSN:
0009-2940
Keywords:
Bicyclo[3.3.0]octadienes, derivatives of
;
Bromination, allylic, by N-bromosuccinimide
;
Zinc-copper couple
;
Semibullvalenes, 1,5-dimethyl-, 2,6- and 3,7-substituted
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 2,6- (6b, c) and 3,7-substituted 1,5-dimethylbicyclo-[3.3.0]octadienes C2- and Cs-9b and c are brominated by N-bromosuccinimide in the allylic positions to afford the dibromides 7b, exo,exo-7c, 10b and c, respectively. An excess of N-bromosuccinimide converts 10b into the unsymmetrical tetrabromide 11. On chromatography over silica gel, exo,exo-7c is epimerized to endo,endo-7c, while methanolysis occurs on reversed-phase chromatography yielding the dimethoxy compound 8. Under ultrasonic irradiation, the zinc-copper couple converts the bromides 7b, exo,exo-7c, 10c, and 11 into the semibullvalenes 1b, c, 2c, and 12 which are persistent in dilute solutions when atmospheric oxygen is strictly excluded. The UV/Vis spectra of 1b, c, 2c, and 12 have been recorded during reversed-phase HPLC on a Bruker ChromScan detector. Notwithstanding the absence of a classical chromophor, 1c does absorb at no less than 450 nm.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921251222
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