The ring closure reaction in 1,6-methano-[10]annulene

The experimental data on a series of 11,11‐disubstituted methane‐[10]annulenes and 11,11‐disubstituted tricyclo[4,4,1,01,6]undeca‐2,4,7,9‐tetraenes allow the estimation of the molecular geometry along the ring closure reaction path for the parent hydrocarbon. Ab initio calculations of the energy as a function of the reaction coordinate indicate the existence of two minima corresponding to the open and closed structures.