Cascade Spirocyclization–Difunctionalization or Rearrangement of Bicyclobutyl-Tethered Aldehyde Hydrazones via Strain Release

Abstract A cascade spirocyclization–difunctionalization of bicyclobutyl-tethered aldehyde hydrazones with N-halosuccinimides was smoothly performed to access diverse halo-succinimide-containing diazaspiro[3.3]heptan-3-ones. Meanwhile, the three-component rearrangement of bicyclobutyl-tethered aldehyde hydrazones, N-halosuccinimides, and NH-sulfoximines also proceeded under similar conditions to give various halo-sulfoximine-featured phenyldiazenyl cyclobutane-1-carboxamides. In addition, some scaled-up experiments and complex substrates were explored in system application studies. Finally, a plausible reaction process was proposed according to mechanistic studies.