A novel synthesis of 1,4-diazabicyclo[3,3,1]octan-3-one derivatives using a traceless-solid-phase approach is described, in which many kinds of 1,4-diazabicyclo[3,3,1]octan-3-one derivatives have been efficiently obtained in high purity, based on an intramolecular alkylation of tertiary amines followed by an elimination of desired tertiary amines from the generated quarternary ammonium salts.