Singlet photosensitization of simple alkenes. Part 2. Photochemical transformation of cyclo-octa-1,5-dienes sensitized by aromatic ester
作者:Seizi Goto、Setsuo Takamuku、Hiroshi Sakurai、Yoshihisa Inoue、Tadao Hakushi
DOI:10.1039/p29800001678
日期:——
Irradiation of an oxygen-free pentane solution of cis,cis- or cis,trans-cyclo-octa-1,5-diene, (1 cc) or (1 ct), in the presence of methyl benzoate as sensitizer gave the cis,trans-isomer and tricyclo[3.3.0.02,6]octane. However, the tricyclo-octane was not an immediate product from (1 cc), but was formed via(1 ct). Kinetic evidence and energetic considerations indicate a non-vertical singlet sensitization
在苯甲酸甲酯作为敏化剂的情况下,辐照顺式,顺式或顺式,反式-环-辛-1,5-二烯(1 cc)或(1 ct)的无氧戊烷溶液,得到顺式,反式异构体和三环[3.3.0.0 2,6 ]辛烷。但是,三环辛烷不是(1 cc)的直接产物,而是通过(1 ct)。动力学证据和精力充沛的考虑表明,涉及单线态激基复合物的非垂直单线态敏化机理,其继而分解而留下了环辛二烯的扭曲,激发的单线态。两个激发络合物,实施例1和实施例2的,因此两个扭绞单环-辛二烯,Ç,1个p和吨,1个p,被假定以理顺的(1不同的反应性毫升)和(1克拉)。从淬灭速率常数中未发现两个双键之间跨环相互作用的证据。环辛二烯和环辛烯的猝灭速率常数与氧化电位之间的相关性表明了该激基复合物的电荷转移特性。手性芳族酯敏化的不对称顺式-反式光致异构化也支持具有相当刚性结构的激基复合物的参与。