Umpolung of <i>N</i>‑Tosylhydrazones:\nSynthesis of <i>N</i>‑Cyano Tosylhydrazones and Their\n[3,3]-Sigmatropic Rearrangement to 2‑Aminoimidazoles

The umpolung of <i>N</i>-tosylhydrazones was reported\nfor the first time. Synthesis of <i>N</i>-cyano tosylhydrazones\nwas developed, and various <i>N</i>-cyano tosylhydrazones\nwere prepared in good yields. An umpolung <i>N</i>-tosylhydrazones\nmechanism was proposed. Meanwhile, the [3,3]-sigmatropic rearrangement\nof <i>N</i>-cyano tosylhydrazones was examined, and the\ncorresponding 2-aminoimidazoles were given.