Photochemical reactions. 132nd communication. Photochemistry of 5,6-epoxy-5,6-dihydro-7-methyl-?-ionine: Influence of a methyl group at the enone side chain on the oxirane cleavage
作者:Antoni Siewnski、Barbara Henggeler、Hans Richard Wolf、Bruno Frei、Oskar Jeger
DOI:10.1002/hlca.19840670115
日期:1984.2.1
1n, π*-Excitation of the γ,δ-epoxy-enone (E)-3 leads exclusively to the conformers (Z)-3A + B. On 1π, π*-excitation of (E)-3, in addition to (Z)-3A + B, products 6–9 arising from a carbene intermediate e are formed. However, products of an isomerization via C(γ), O-bond cleavage of the oxirane were not formed on either mode of excitation. On thermolysis, at 80° the conformer (Z)-3A is transformed into
1 n时,γ,δ-环氧烯酮(的π* -Excitation ë) - 3根引线专门向构象异构体(Ž) - 3A +乙。上1个π,π* -excitation(的ë) - 3中,除了(Ž) - 3A +乙,产品6-9从形成中间体e卡宾产生。但是,在两种激发方式下均未形成通过C(γ)异构化,环氧乙烷的O键裂解的产物。在热解时,构象异构体(Z)-3A在80°转变为(Z)-3B,在光解时返回(Z)-3A和(E)-3。然而,在160°,(Z)-3B重排为异构体6、10和11。