作者:Harold Hart、Sun-Mao Chen、Makoto Nitta
DOI:10.1016/s0040-4020(01)92380-4
日期:——
Two bicyclo[3.2.n]dienones, which differ from one another only by the presence or absence of an O atom as the “n” bridge, show very different pbotoisomerization behavior. Irradation of hexamethyl-8-oxabicyclo[3.2.1]octadienone 12 gives endo-6-acetylpentamethylbicyclo[3.1.0]hexenone 16, probably via an initial [1,3] sigmatropic rearrangement (Scheme 3). In contrast, hexamethylbicyclo[3.2.0]heptadienone
两个双环[3.2.n]二烯酮彼此之间的区别仅在于存在或不存在作为“ n”桥的O原子,它们表现出截然不同的磷酸化异构化行为。六甲基-8-氧杂双环[3.2.1]辛二烯酮12的辐照可能会产生初始的[1,3]σ重排(图3),生成内基-6-乙酰基五甲基双环[3.1.0]己烯酮16。相反,六甲基双环[3.2.0]庚二烯酮14通过初始的[3,3]-σ重排而光异构化,分离出的产物是相对稳定的环戊二烯-烯酮26。14(即32)的亚甲基类似物进行类似的重排。生成丙二烯33和炔烃34。讨论了这些光异构化的机理。