Synthesis of certain tricyclic systems containing a bridgehead nitrogen

We have shown that treatment of a quinoline Reissert compound carrying a blocking group at the 4-position with base in the presence of acrylonitrile can lead in modest yield to the pyrrolo[1,2-a]quinoline system and to an open chain ketone derived via an intermediate tetrahydropyrrolo[1,2-a]quinoline. This behaviour contrasts with the more ready formation of the pyrrolo[2,1-a]isoquinoline system by a similar process. Analogous condensation of the corresponding phthalazine Reissert compound with acrylonitrile in base has been shown to provide a straightforward route to the little known pyrrolo[2,1-a]phthalazine system. [Continues.]