Heptacyclo[19.3.0.0 1,5 .0 5,9 .0 9,13 .0 13,17 .0 17,21 ]‐tetracosane([6.5]coronane)

Radical cyclization of 1 provided the first route to an [m.n]coronane. the title compound 2 . The main product, however, is the heptacyclic compound 3 . The coronane 2 has an all‐ cis configuration, exists in the chair conformation, and undergoes inversion extremely rapidly with Δ G   173 ≠≤ 36 kJ mol −1 (AIBN = azobisisobutyronitrile).