anthrene and 1‐cyclobutylidene‐1a,9b‐dihydro‐1H‐cyclopropa[l]phenanthrene undergo photolysis in solution at ambient temperature to produce cyclohexyne and cyclopentyne, respectively. These strained cycloalkynes, formed via the putative cycloalkylidenecarbenes, were intercepted as Diels–Alder adducts. Calculations at the CCSD(T)/cc‐pVTZ//B3LYP/6‐31+G* level of theory show that singlet cyclopentylidenecarbene
烃1–环亚戊基-1a,9b-二
氢-1H-
环丙烷[ l ]
菲和1–
环丁烯-1a,9b-二
氢-1H-
环丙烷[ l ]
菲在环境温度下在溶液中发生光分解以生成
环己炔和环戊炔。这些通过假定的亚
环烷基
碳烯形成的应变
炔烃被截获为狄尔斯-阿尔德加合物。在CC
SD(T)/ cc-pVTZ // B3LYP / 6-31 + G *理论
水平上的计算表明,单重态环戊叉
碳烯必须克服9.1 kcal mol -1的障碍才能重排成
环己炔(使用ΔE进行环扩环) = -15.1大卡摩尔-1)。相比之下,
环丁烯卡宾仅需克服1.6 kcal mol -1的势垒即可重排成环戊炔(环扩展的ΔE = -6.2 kcal mol -1)。