title: Photochemical ring opening of 7-benzoyl- and 7-methoxycarbonyldibenzonorcaradienes. competing 1,2-hydrogen shift and cyclization reactions of 1,3-diradicals.
abstract: [see reaction]. The UV irradiation of dibenzonorcaradienes bearing an acyl or alkoxycarbonyl substituent in the 7-position results in formation of substituted phenanthrenes, as well as cis-trans isomerization of the starting material. This reaction apparently proceeds via intermediate formation of a short-lived (tau = 1-20 ns) 1,3-diradical, which is produced by photochemical cleavage of one cyclopropane bond, while no evidence of alpha-carbonylcarbene formation was found.
authors.affiliation: Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bogdanova
authors.forename: V V
authors.initials: VV
authors.lastname: Popik