Fig. 2: Strategies and methods in synthesizing hexahydro-1,4-methanocarbazole ring.

Traditional methods involved palladium-catalyzed direct condensation, or electrophilic insertion by external amine surrogates. In contrast, “detour” strategy in this work employed successive generation of two key phenylnorbornyl palladium species to construct the hexahydro-1,4-methanocarbazole core and introduce 5-substitution in tandem. Ligands to PdII, and electrophile-PdIV complexes were omitted when illustrating for the sake of clarity.