Synthesis of C_11N_5 marine sponge alkaloids: (±)-hymenin, stevensine, hymenialdisine, and debromohymenialdisine

摘要

The synthesis of C_11N_5 marine sponge alkaloids (±)-hymenin (1), stevensine (2) hymenialdisine (3), and debromohymenialdisine (4) is described. These natural products are the primary family members of the sponge metabolites that contain a fused pyrrolo[2,3-c]azepin-8-one ring system with either a 2-aminoimidazole (AI) or glycocyamidine appendage. The key steps in the synthesis centered around the generation of novel azafulvenium ions and their regioselective hetrodimer- ization with AI in order to create the tricyclic core.