ISSN:
1572-9001
Keywords:
4,4′-Bi-4H-cyclopenta[def]phenanthrylidene
;
oxidative electrocyclization
;
Diels-Alder adduct
;
pentafulvene
;
distorted alkenes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The twisted pentafulvene, 4,4′-bi-4H-cyclopenta[def]phenanthrylidene, does not undergo oxidative electrocyclization to a semibuckminsterfullerene under photo-oxidative conditions. However, the use of standard dehydrogenating agents such as DDQ or tetrachloro-2,3-benzoquinone at 200°C resulted in partial oxidative electrocyclization and formation of a Diels–Alder adduct, respectively. The crystal structure of this Diels-Alder adduct was obtained and shown to possess C2 symmetry. The crystal structure for 4,4′-bi-4H-cyclopenta[def]phenanthrylidene was also obtained and the molecular parameters differ slightly from what was previously reported for the same compound. Molecular modeling of this pentafulvene gave a twist angle matching the crystal structure. Similar modeling of related bifluorenylidene, bis-1,1′-indenylidenes and biscyclopentadienylidene gave twist angles which correlate with the computed heats of hydrogenation for the bridging alkene unit.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009262209989
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