Aromaticity and Extrusion of Benzenoids Linked to [o‐COSAN]−: Clar Has the Answer

AbstractBenzene and pyrene can be synthetically linked to [o‐COSAN]− keeping their aromaticity. In contrast, naphthalene and anthracene are extruded in the same reaction. We have proven that extrusion is only favorable if the number of Clar’s π‐sextets remains constant. Thus, Clar has the answer to whether an attached polycyclic aromatic hydrocarbon to [o‐COSAN]− is extruded or not.