Photoinduced Electron-Transfer Cope Rearrangements of 3,6-Diaryl-2,6-octadienes and 2,5-Diaryl-3,4-dimethyl-1,5-hexadienes: Stereospecificity and an Unexpected Formation of the Bicyclo[2.2.0]hexane Derivatives
作者:Hiroshi Ikeda、Toshihiko Takasaki、Yasutake Takahashi、Akinori Konno、Masao Matsumoto、Yosuke Hoshi、Takashi Aoki、Takanori Suzuki、Joshua L. Goodman、Tsutomu Miyashi
DOI:10.1021/jo981775h
日期:1999.3.1
photoinduced electron-transfer Cope rearrangements of the 4-methylphenyl derivatives are concurrent with the formation of trans- or endo,cis-1,4-bis(4-methylphenyl)-2,3-dimethylbicyclo[2.2.0]hexane in a Cope photostationary mixture. Observed stereospecificity of the Cope rearrangement and the formation of the bicyclo[2.2.0]hexane derivatives demonstrate the intermediacies of both the chair and boat 1,4-diaryl-1
在9,10-二氰基蒽敏感的光致电子转移条件下,(Z,Z)-,(E,E)-,(E,Z)-3,6-diaryl-2,6-octadiene和(d, 1),(内消旋)-2,5-二芳基-3,4-二甲基-1,5-己二烯立体定向地进行Cope重排,得到Cope光固定混合物。值得注意的是,4-甲基苯基衍生物的光诱导电子转移Cope重排与顺式或内式顺-1,4-双(4-甲基苯基)-2,3-二甲基双环[2.2.0]己烷的形成同时发生在应付光致静止混合物中。观察到的Cope重排的立体特异性和双环[2.2.0]己烷衍生物的形成证明了椅子和船用1,4-二芳基-1,2-二甲基环己烷-1,4-二基和阳离子自由基中间体的中间体应对重排周期。反式和反式,顺-1,4-二芳基-5,6-二甲基-2,3-二氮杂双环[2.2.2]辛-2-烯进一步支持二甲醚中间体在Cope重排循环中的干预。通过光声分析,提出了一种阳离子自由基环化-双