O–N–O Triple Hydrogen Atom Transfer: TEMPO-Initiated Synthesis of Symmetric and Asymmetric Disulfides

We report the first triple hydrogen-atom transfer (HAT) strategy for the efficient synthesis of symmetric and asymmetric disulfides. This metal-, oxidant-, and solvent-free reaction proceeds under mild conditions with excellent functional-group tolerance and a broad substrate scope. Mechanistic studies indicate that TEMPO-derived O-centered radical and N- and O-centered radicals formed via thiol-assisted N–O bond cleavage engage in the triple HAT process with thiol substrates.