Diphenylmethylidenecyclobuta[a]cyclopropa[d]benzene: synthesis and spectral characterization

[reaction: see text] The first derivative of the novel and highly strained rocketene (cyclobuta[a]cyclopropa[d]benzene) 5, namely, the C4 diphenyl-substituted exocyclic alkene 8, has been prepared in 16% overall yield as a yellow oil with properties fully consistent with its highly strained nature.