This highlight review describes the syntheses of 2-azabicyclo-[3.3.1]nonanes, focusing on synthetic studies of the macrocyclic diamine alkaloids, sarain A and madangamines. These alkaloids have a 2-azabicyclo[3.3.1]nonane that is fused with an N-heterocycle. Researchers employed unique strategies to construct different structures with additional substituents and functional groups in the target molecule.