Photorearrangement of 4,4-Dimethylcyclohex-2-enones with Alkyl or Fluoro Substituents at C(5) and C(6): In Search of the Mechanism
作者:Giuliano Cruciani、Paul Margaretha
DOI:10.1002/hlca.19900730415
日期:1990.6.20
three-membered ring in trans-configuration, while 6-fluorocyclohex-2-enones 4d and 4f afford mixtures of diastereoisomeric bicyclohexanones. Mechanistic conclusions regarding an intermediate trimethylene biradical are presented.
研究了环己-2-烯酮4a-h对双环[3.1.0]己-2-烯酮5和环戊-2-烯酮6(λ= 350 nm,MeCN)的光重排。两者的量子产率(Φ -4 = 0.004- 0.024)和产品比率(5/6 = 65:35-31:69)变化仅在一个相当小的范围内,指示该重排是相对不敏感的基于C的取代基( 5)或C(6)。在C(6)或C(5)上仅具有一个烷基的化合物4b,4c和4g选择性地重排为具有烷基和三元环反式构型的非对映异构体5,而6-氟环己基-2-烯酮4d和4f提供非对映异构体双环己酮的混合物。提出了有关中间体三亚甲基双自由基的机械结论。