The intermediary-produced CF2H radical, produced by one-electron oxidation of difluoromethylborates [pinB(Aryl)CF2H][K(18-cr-6)] using photo-redox catalysts, is advantageous for synthesizing the difluoromethylated benzene-fused γ-sultams.
The sulfonamide scaffold is widely applied in drug discovery. In recent years, there has been growing investigation on cyclic sulfonamides (sultams) as they offer much potential in combating various diseases.
γ-Sultams bearing a trifluorinated ethyl- or an ene-gem-difluorinated tether were obtained from CF3-substituted N-allenamides; experimental and DFT calculations suggested that this transformation involves a 5-endo-dig cyclization on the ene-ynamide generated in situ.
An asymmetric aza-Friedel–Crafts arylation of biphenyl-bridged seven-membered cyclic N-sulfonylimines with indolizines via chiral phosphoric acid is realized, affording chiral indolizine modified ε-sultams with up to 99% yield and 99% ee.
An electrochemical three-component transformation between N-cyanamide alkenes, Na2S2O5 and sulfonyl hydrazides is described, through which various sulfonylated fused sultams were prepared in a sustainable and modular fashion.