Imino‐bridged heterocycles. III . Synthesis of mono‐bridgehead substituted 11H‐benzo[5,6]cyclohepta[1,2‐c]pyridin‐6,11‐imines by regiospecific amine to olefin cyclizations

Employing regiospecific amine to endocyclic olefin and hydroxylamine to exocyclic olefin cyclizations, we have developed pathways to two isomeric, bridgehead methyl‐substituted benzo[5,6]cyclohepta[1,2‐c]pyridin‐6,11‐imines. Acid catalyzed cyclization of 5 to 6 was accomplished under exceedingly mild conditions (silica gel/chloroform), whereas, thermal cyclization of 20 to generate 21 was performed analogously to the dibenzo[ a,d ]cyclohepten‐5,10‐imine system.