Electrochemical Oxidative [4+2] Annulation for the π-Extension of Unfunctionalized Heterobiaryl Compounds

Considering their unique electronic properties and diverse biological activities, regioselective access to fused aromatic compounds is significantly important in the field of organic materials and pharmaceutical science. Herein, we developed electrochemical oxidative [4+2] annulation reactions of heterobiaryl compounds with alkynes or alkenes, leading to the formation of several polycyclic heteroaromatic compounds. This electrosynthetic methodology serves for the straightforward pi-extension of unfunctionalized heterobiaryl compounds. The requirements of additional oxidants and prefunctionalization of starting materials are obviated. Through the in situ generation of heterobiaryl radical cation intermediates, various fused aromatic compounds were obtained with good yields and excellent regioselectivity.