propyne. The carbene X, showing behaviour typical of vinyl carbenes, undergoes addition to the adjacent double bond furnishing the cyclopropene 11. The carbene XI, however, undergoes an insertion reaction into the neighbouring oxirane C,C-bond leading to the oxetene (E)-21 which can be isolated at −78°, but at room temperature is rapidly transformed to the aldehyde 10. On triplet excitation (acetone
在单线激发(λ= 254nm,
乙腈)上,二环氧二烯(E)-7经历光裂解为羰基内酯VII和碳烯X和XI。羰基内酯VII重排成热不稳定的二氧杂双环[3.2.1]
辛烯20或片段,通过VIII重排成醛9和
丙炔。卡宾X,表现出
乙烯基卡苯的典型行为,除提供相邻的双键外,还提供了环
丙烯11。卡宾十一然而,在邻近的
环氧乙烷C,C键中进行插入反应,导致生成
环氧乙烷(E)-21,该
环氧乙烷可在-78°分离,但在室温下会迅速转化为醛10。然而,在三重态激发下(
丙酮,λ> 280 nm),(E)-7显示环氧二烯的典型行为,经历
环氧乙烷的C,O裂解并异构化为22、23和(E / Z)-24。