Photochemical Rearrangement of Enediynes: Is a “Photo-Bergman” Cyclization a Possibility?
作者:Ariella Evenzahav、Nicholas J. Turro
DOI:10.1021/ja9722943
日期:1998.3.1
when the double bond of the enediyne was of aromatic character. Triplet sensitization studies and laser flash photolysis experiments point toward radical mechanisms taking place during formation of both classes of products, with the photoreduction products forming from the excited triplet state and the cyclized naphthyl products forming from either the singlet or the triplet states. For the cyclization
烯二炔 1 和 2 在 2-丙醇中光解以产生类似于热伯格曼环化机制的产物。此外,还形成了烯二炔官能团的三键之一的光还原产物。发现产物分布和产率取决于三键上的取代基和双键的性质;特别是三键上的苯基取代基消除了光还原产物,当烯二炔的双键具有芳香性时,总产率更高。三重敏化研究和激光闪光光解实验表明在这两类产品的形成过程中会发生自由基机制,由激发三重态形成的光还原产物和由单重态或三重态形成的环化萘基产物。对于环化反应,取代的 1,4-脱氢萘双自由基物种,结构上...