Novel Synthetic Approach towards Amino-Substituted Polycyclic Aromatic Hydrocarbons through Electrocyclization of Keteniminium Salts

Polycyclic aromatic hydrocarbons (PAHs) are an important family of molecules in science and technology. Amino-substituted PAHs are promising building blocks to create attractive molecules for materials science. However, the synthetic limitations have hampered to produce diverse structures of amino-substituted PAHs. Here we describe a novel efficient synthetic method to access amino-substituted PAHs through the electrocyclization of highly reactive keteniminium species. We demonstrated the synthesis of various amino-substituted PAHs and disclosed some of their photophysical properties. Furthermore, combination with theoretical calculation revealed that the multiple electrocyclization reactions of keteniminium species is a stepwise process and the fusion of additional aromatic ring to the substrate accelerates the electrocyclization.