Several Diels-Alder adducts between benzoquinones and cyclopentadiene were reduced to the corresponding diols 7a-c and 11. Treatment of these diols with strong acid triggered a skeletal rearrangement reaction resulting in compounds 8a-c and 12 that contain a 4,8-methanoazulene substructure. In addition, a dyotropic-like rearrangement of the tetracyclic lactone 13 to the spiro-lactone 18 was observed. Five
苯醌和
环戊二烯之间的几种Diels-Alder加合物被还原为相应的二醇7a-c和11。用强酸处理这些二醇会引发骨架重排反应,从而导致化合物8a-c和12包含4,8-甲基氮杂氮杂亚结构。另外,观察到四环内酯13向
螺内酯18的类似发各向异性的重排。X射线分析支持了其中的五个结构。