An Unexpected Spirocyclic Compound by the Scholl Reaction

The Scholl reaction is a powerful synthetic method for polyaromatics through intramolecular C–C bond formation. In this work, three substrates were prepared to examine their potential to generate heptagon‐embedded polycyclic compounds under the conditions of the Scholl reaction. Interestingly, two spirocyclic compounds bearing a pentagonal ring were obtained and fully characterized by single‐crystal X‐ray diffraction. The cation radical mechanism of the Scholl reaction was adapted to explain these unexpected results. Our study enriches the understanding of the Scholl reaction and offers a useful hint when designing proper substrates for polycyclic aromatic nanocarbons.