Flash Vacuum Pyrolysis of 5-Diazodibenzocycloheptene. Some Insights into Aromatic Carbene-Arylcarbene Rearrangement

Article abstract of DOI:10.1246/bcsj.64.327

Flash vacuum pyrolysis of the title diazo compound gives 4H-cyclopentaphenanthrene, which is interpreted as indicating that dibenzocycloheptatrienylidene (13) undergoes the carbene-carbene rearrangement to generate 4-phenanthrylcarbene.The reactivities of 13 are compared with those of other benzoannulated cycloheptatrienylidenes and discussed in terms of the effect of the benzo ring to the activation energy for the rearrangement.