- Preparation of Benzocyclobutenones via the Photochemical Cyclization of 1-(ortho-Alkylary)-2,2,4-trimethylpentane-1,3-diones
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Irradiation of 1-(ortho-methylaryl)- and 1-(ortho-ethylaryl)-2,2,4-trimethylpentane-1,3-diones 4a-g in hexane gave benzocyclobutenols 10a-g.However, irradiation of 1-(ortho-isopropylaryl)-2,2,4-trimethylpentane-1,3-diones 4i and 4j resulted in no reaction.Irradiation of 1-mesityl-2,2,4-trimethylpentane-1,3-dione 4h gave a complex mixture of products.Pyrolysis of benzocyclobutenols 10a, b, d-f gave benzocyclobutenones 11a, b, d-f and 2,4-dimethylpentan-3-one 2, whereas that of the benzocyclobutenols 10c, g gave the starting 1,3-diketones 4c, g predominantly along with small amounts of benzocyclobutenones 11c, g and the dimethylpentanone 2.
- Yoshioka, Michikazu,Momose, Shinobu,Nishizawa, Kaori,Hasegawa, Tadashi
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p. 499 - 503
(2007/10/02)
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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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