A missing member of conjugated N-heterocycles: realizing pyrido[1,2-α]azepine by reacting ruthenium alkenylcarbene complex with alkyne.

Despite the excellent chemical properties of N-heterocycles, pyrido[1,2-α]azepine remains elusive due to its potential antiaromaticity and lability. Herein, we demonstrate the synthesis and characterization of the first bicyclic pyrido[1,2-α]azepine that leverages the coordination to the ruthenium center to promote the stability of N-bridged bicycle. [ABSTRACT FROM AUTHOR]