Recently, naphthalenoide derivatives of Troger's base (TB) have become important as structural compartments of molecular tweezers and compounds with high specific rotation. The formation of TB derivatives and byproducts from naphthalen-2-amine, methyl 6-aminonaphthalene-2-carboxylate, and anthracen-2-amine was studied. It was discovered that the formation of a naphthalenoide TB derivative is followed by the formation of a unique structural isomer of TB: spiroTB.