SULFENAMIDES AND SULFINAMIDES X OXIDATION OF THIOLS BY ARYL SULFINAMIDES

A dissection has been made of the oxidation of thiols by aryl sulfinamides, with the process explained by initial protonation of the sulfinyl group followed by a series of nucleophilic displacements, the first of which gives thiosulfinate and elimination of amine. The more usual reaction with thiosulfinate then gives disulfide, and sulfenic acid as a transitory intermediate, which by reaction with a third mode of thiol yields more disulfide. Reactions with lesser amounts of thiol permitted identification of intermediates. The effect of activation of the thiol is discussed. In contrast with oxidations by simpler sulfoxides the reaction proceeds without acid catalysis at ambient temperature, confirming the susceptibility to fission of the S—N bond in polar reactions.