(1α,2α, 7α,8α,12α,17α,18α,19α)‐Heptacyclo[17.3.1.18,12.05,23.06,18.07,17.016,24]‐tetracosa‐5(23),16(24)‐dien, ein hyperstabiles Alken

(1α,6α,7α,8α,12α,17α,18α,19α)‐Heptacyclo[17.3.1.18,12.05,23.06,18.07,17.016,24]tetracosa‐5(23),16(24)‐diene, a Hyperstable Alkene Hydrogenation of the cis‐photodimer 1 of acenaphthylene yields the title compound 2, which, though still containing two double bonds, undergoes no further hydrogenation or reaction with bromine for steric reasons. The cyclobutane ring of 2 shows strong steric distortions as revealed by X‐ray analysis as well as by force‐field and semiempirical MO calculations. Boldt*, P., Döring, D., Jones, P. G., Köpper, H., Trog, R.‐S. (1α,6α,7α,8α,12α,17α,18α,19α)‐Heptacyclo[17.3.1.18,12. 05,23.06,18.07,17.016,24]tetracosa‐5(23), 16(24)‐dien, ein hyperstabiles Alken (1α,6α,7α,8α,12α,17α,18α,19α)‐Heptacyclo[17.3.1.18,12. 05,23.06,18.07,17.016,24]tetracosa‐5(23), 16(24)‐diene, a Hyperstable Alkene