Grota, Juliane Mattay, Jochen Piech, Krzysztof Bally, Thomas 2006 Three tricyclic vinylcyclobutanes (3-methylenetricyclo[5.3.0.0^2,6]decanes <b>1</b>-<b>3</b>) have been subjected to ionization by photoinduced electron transfer in solution and by X-irradiation in Ar matrices. All three compounds undergo oxidative cycloreversion; the cleavage of the four-membered ring, however, occurs in a different direction depending on the presence of a methyl group in position 6 of the tricyclic framework. In those derivatives, cycloreversion is found to lead to 1-methyl-8-methylene-1,6-cyclodecadiene radical cations (<b>5^.</b>⁺ from <b>1</b>, <b>8^.</b>⁺ from <b>2</b>) which upon back electron transfer yield two different hydrocarbons (<b>6</b> from <b>5^.</b>⁺, <b>9</b> from <b>8^.</b>⁺), depending on the configuration around the endocyclic double bonds of the respective cyclodecadiene derivative. In the absence of a methyl group on C6, the cycloreversion leads to a radical cation complex between 1-methylenecyclopent-2-ene and cyclopentene (<b>12^.</b>⁺) which appears to revert to <b>3</b> on back electron transfer. The intermediate radical cations <b>5^.</b>⁺, <b>8^.</b>⁺, and <b>12^.</b>⁺ have been identified and characterized by UV/Vis and IR spectra in Ar matrices. The mechanism of their formation is elucidated by quantum chemical calculations. application/pdf https://folia.unifr.ch/global/documents/300137 https://folia.unifr.ch/documents/300137/files/bally_ort.pdf https://folia.unifr.ch/documents/300137/files/bally_ort_am.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1002/chem.200501338 info:eu-repo/semantics/openAccess License undefined Chemistry - A European Journal. - 2006, vol. 12, no. 17, p. 4559-4567 cycloreversion matrix isolation photoinduced electron transfer quantum chemical calculations radical ions info:eu-repo/classification/udc/54 Oxidative rearrangements of tricyclic vinylcyclobutane derivatives http://purl.org/coar/resource_type/c_6501