I2-Promoted oxidative annulation of three different amines to access diverse biheteroaryls†

Utilizing tertiary alkylamines as reliable two-carbon building blocks, a concise and efficient route for the regioselective synthesis of biquinolines from 2-methylquinolines and arylamines has been established. This I₂-promoted approach enables a [4π + 2σ] annulation of three nucleophilic species via two kinds of transient enamines. The C(sp³)–H annulation strategy is also extended to other methylazaarenes toward constructing nonsymmetrical benzo[f]quinoline-containing biheteroaryls. Notably, the applicability of this process for the late-stage functionalization of complex molecules highlights its considerable potential for application in biorelevant areas.