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Abstract The unique features of the sulfenamides’ S(II)-N bond lead to interesting stereochemical properties and significant industrial functions. Here we present a chemoselective Chan–Lam coupling of sulfenamides to prepare N -arylated sulfenamides. A tridentate pybox ligand governs the chemoselectivity favoring C–N bond formation, and overrides the competitive C-S bond formation by preventing the S,N-bis-chelation of sulfenamides to copper center. The Cu(II)-derived resting state of catalyst is captured by UV-Vis spectra and EPR technique, and the key intermediate is confirmed by the EPR isotope response using 15 N-labeled sulfenamide. A computational mechanistic study reveals that N -arylation is both kinetically and thermodynamically favorable, with deprotonation of the sulfenamide nitrogen atom occurring prior to reductive elimination. The origin of ligand-controlled chemoselectivity is explored, with the interaction between the pybox ligand and the sulfenamide substrate controlling the energy of the S -arylation and the corresponding product distribution, in agreement with the EPR studies and kinetic results.
Han et al. (Tue,) studied this question.