Expedient Access to gem-Difluoromethyl Cyclic Sulfamidates via Mannich Reaction and Reductive C-C Bond Fission

A concise synthesis of gem-difluoromethyl-embedded cyclic sulfamidates is described, wherein in situ generated gemdifluoroenolates undergo a Mannich reaction with cyclic sulfamatederived imines to afford β-amino-α,α-difluoroketones. Subsequent sequential oxidation and hydride-mediated reduction trigger a C-C bond-cleavage event, ultimately furnishing difluoromethyl-substituted cyclic sulfamidates in high yields. The protocol is operationally simple, scalable, and features a good substrate generality.