An Expedient Iodine‐Catalyzed Synthesis of Unsymmetrical Thiosulfonates by Sulfonylation of Thiols using Sulfonyl hydrazides in the Presence of Oxone

Abstract A metal‐free and green iodine‐catalyzed protocol is described herein for the synthesis of unsymmetrical thiosulfonates by sulfonylation of thiols using I 2 /Oxone. It's shown that oxidative cross‐coupling of thiyl radicals with sulfonyl radicals – generated from thiols and sulfonyl hydrazides, respectively, by the redox chemistry between thiol/Oxone and I 2 /Oxone – occurs in a facile manner at rt, providing access to unsymmetrical thiosulfonates. Diverse unsymmetrical thiosulfonates are synthesized in good‐to‐excellent isolated yields by the reactions of aryl/(hetero)aryl/alkyl thiols with a variety of aryl/(hetero)aryl/alkyl/benzyl sulfonyl hydrazides. The protocol can be further extended to the synthesis of alkyl/aryl sulfonate esters by the reactions of sulfonyl hydrazides with alcohols/phenols using I 2 /Oxone.