CREATION AND CHARACTERIZATION OF CARBENES HAVING UNUSUAL STRUCTURE

虽然已有报道称，二苯亚甲基环丙烷在溶液中被辐照后会生成2，2-二苯基-1-亚甲基环丙烷，但其反应机理尚不清楚。本研究为2，2-二苯基环丁二烯的中间体提供了实验支持。详细的产物分析表明，除2，2-二苯基-1-亚甲基环丙烷外，还生成了2，2-二苯基环丁烯。与母体苯基卡宾不同的是，苯环丁烯从未被直接观察到。我们对这种特殊的卡宾很感兴趣，并试图从前体生成苯环丁烯亚甲基，以考察其活性。苯环丁烯酮的N-(2-苯基)亚胺光解生成苯环丁烯亚基的二聚体和三聚体。在烯烃或甲醇存在的情况下，类似的光解会导致环丙烷或甲氧基苯并环丁烯的形成。尽管N-(2-苯基赖氨基)亚胺的稳态光解提供了苯环丁烯的产物，但即使在我们的激光闪光光解条件下，它也是难以捉摸的。然而，研究表明，吡啶似乎能捕获苯环丁二烯给出一个叶立德。

Although it has been reported that irradiation of diphenylmethylenecyclopropane in solution results in its isomer, 2,2-diphenyl-1-methylenecyclopropane, little has been known on the mechanism. The present study provides experimental support for the intermediacy of 2,2-diphenylcyclobutylidene. The detailed product analysis showed that 2,2-diphenylcyclobutene is formed in addition to 2,2-diphenyl-1-methylenecyclopropane. Similar photoreaction under oxygen afforded 2,2-diphenylcyclobutanoneas well.In contrast to parent phenylcarbene, benzocyclobutenylidene has never been observed directly. We are interested in this particular carbene and have attempted to generate benzocyclobutenylidene from precursors in order to investigate its reactivity.Photolysis of N-(2-phenylazyridyl)imine of benzocyclobutenone results in dimers and trimers of benzocyclobutenylidene. Similar photolysis in the presence of alkenes or methanol leads to formation of cyclopropanes or methoxybenzocyclobutene. It is most likely that benzocyclobutenylidene is involved in the photoreactions.Although the steady-state photolyses of the N-(2-phenylazyridyl)imine afford products suggestive of benzocyclobutenylidene, it is elusive even under our laser flash photolytic conditions. However, it is shown that pyridine seems to trap bensocyclobutelideneto give a ylide.