Synthesis of <i>C</i>‑Unsubstituted 1,2-Diazetidines and Their Ring-Opening Reactions via Selective N–N Bond Cleavage

<i>C</i>-Unsubstituted 1,2-diazetidines, a rarely studied type of four-membered heterocyclic compounds, were synthesized through an operationally simple intermolecular vicinal disubstitution reaction. 1,2-Diazetidine derivatives bearing various <i>N</i>-arylsulfonyl groups were readily accessed and studied by experimental and computed Raman spectra. The ring-opening reaction of the diazetidine was explored and resulted in the identification of a selective N–N bond cleavage with thiols as nucleophiles, which stereoselectively produced a new class of <i>N</i>-sulfenylimine derivatives with <i>C</i>-aminomethyl groups