The synthesis of naphthyridone derivatives containing 8-alkoxyimino-1, 6-dizaspiro [3.4] octane scaffolds, the position isomers of the side chain at the C-7 position of Zabofloxacin, has been achieved in eight steps from tert-butyl 3-cyano-4-oxopyrrolidine-1-carboxylate. The possible reaction mechanisms were also proposed. The key spirocyclic carbamate esters, which could be prepared using a modified Hofmann rearrangement strategy, were ...