- Generation of 6-methylene-2,4-cyclohexadienylideneketene by flash photolysis of benzocyclobutenone in aqueous solution and study of the reactions of this ketene in that medium
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Flash photolysis of benzocyclobutenone in aqueous solution produced a transient species with a microsecond lifetime whose rates of decay were measured in perchloric acid, sodium hydroxide, and buffer solutions over the acidity range [H+] 1 × 10-13 - 100 M. This produced a rate profile, isotope effects, and buffer behaviour typical of ketene reactions, and that, together with product identification, served to identify this transient as 6-methylene-2,4-cyclohexadienylideneketene, formed by electrocyclic opening of the four-membered ring of benzocyclobutenone. Comparison of rates of reaction of this ketene with those of its saturated analog, pentamethyleneketene, produced some expected as well as some unexpected results.
- Chiang,Kresge,Zhan
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- THERMAL ADDITION REACTIONS TO BENZOCYCLOBUTENONES STUDIED BY FLASH PHOTOLYSIS
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Ortho-quinoid vinylketenes 2 have been generated thruogh flash photolysis of benzocyclobutenones 1.A kinetic study of intermolecular addition reactions of 2 competing with the recyclization 2 -> 1 reveals strikingly different substituent effects for the addition of methanol and of dienophiles.
- Schiess, P.,Eberle, M.,Huys-Francotte, M.,Wirz, J.
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p. 2201 - 2204
(2007/10/02)
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