One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli-Cushman protocol.

The Castagnoli-Cushman reaction of 3,4-dihydroisoquinolines with glutaric anhydride, its oxygen and sulfur analogues was investigated as a one-step approach to the benzo[]quinolizidine system and its heterocyclic analogs. An extension towards the pyrrolo[2,1-]isoquinoline system was achieved with the use of succinic anhydride. The results are evidence of an unexplored method for the access of the aforementioned tricyclic annelated systems incorporating a bridgehead nitrogen atom.

Natural and synthetic cage compounds incorporating the 2,9,10-trioxatricyclo[4.3.1.03,8]decane type moiety.

The 2,9,10-trioxatricyclo[4.3.1.