From Fenestrindane towards Saddle‐Shaped Nanographenes Bearing a Tetracoordinate Carbon Atom

Two saddle‐shaped polycyclic aromatic compounds ( 8 a and 8 b ) bearing an all‐cis‐[5.5.5.5]fenestrane core surrounded by an o,p,o,p,o,p,o,p‐cyclooctaphenylene belt were synthesized and characterized by NMR spectroscopy and mass spectrometry. The key step of this synthesis involves the formation of four cycloheptatriene rings from the corresponding electron‐rich 1,4,9,12‐tetraarylfenestrindane derivatives 7 a and 7 b in Scholl‐type cyclizations. The structural details of the D 2d ‐symmetric saddle compound 8 a were determined by X‐ray crystallography, and the properties of 8 a and 8 b were studied by UV/Vis and fluorescence spectroscopy and cyclic voltammetry.