Towards Nonalternant Nanographenes through Self‐Promoted Intramolecular Indenoannulation Cascade by C−F Bond Activation

Large polycyclic aromatic hydrocarbons (PAHs) containing pentagons represent an important class of compounds that are considered to be superior materials in future nano‐electronic applications. From this perspective, the development of synthetic approaches to large PAHs and nanographenes (NGs) is a matter of great importance. In this context indenoannulation appears to be the most practical way to introduce pentagons into NGs. Here we report that alumina‐mediated C−F bond activation is an attractive tool for the synthesis of non‐alternant NGs bearing several pentagons. The unique nature of the reaction leads to a rather counter‐intuitive outcome and allows considering each previous aryl–aryl coupling as a promoter of the following one, despite the continuous increase in the strain energy. Thus, the presented strategy combines both facile synthesis and significant yields for large nonalternant PAHs and NGs. Large nonalternant PAHs can be easily accessed by this alumina‐mediated C−F bond activation protocol. The unique nature of the reaction leads to a rather counter‐intuitive outcome, since this strategy works better with the increase of the size system, which is typically vice versa in case of other conventional methods.