ISSN:
0947-3440
Schlagwort(e):
Photochemistry
;
Cage compounds
;
Dewar benzenes
;
Prismanes
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
In this paper we report on the photochemistry of Dewar benzenes bridged at the 1,4- and 5,6-positions and substituted at the 2,3-positions. It was found that simple alkyl substitution leads to prismanes only to a minor extent. Introduction of phenyl groups into the 2- or 2,3-positions gives the corresponding doubly bridged prismanes in yields up to 80% Pentamethylene-bridged bis-Dewar benzenes 19 rearrange upon irradiation to 22. Irradiation of the doubly bridged Dewar benzene derivatives with one ester group at the 5-position does not yield isolable products. However, introduction of one tert-butylsulfonyl group such as 30-33 gives almost quantitative yields of isolable prismanes if pentamethylene or hexamethylene bridges are used. The nonbridged species, 2-tert-butylsulfonyl-1,4,5,6-tetramethylbicyclo[2.2.0]hexa-2,5-diene (44), aromatizes upon irradiation into 1-(tert-butylsulfonyl)-2,3,4,5-tetramethylbenzene (45). In contrast to the pentamethylene-bridged monosulfone 47, the corresponding disulfone 38 undergoes no photochemical reaction. This could be explained by the X-ray structure, which reveals a strong interaction between one of the tert-butyl groups and the pentamethylene chain bridging the double bond in 38.
Zusätzliches Material:
8 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.199619961020
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