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

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.

Automated summary

A metal-free and green iodine-catalyzed protocol is described for the synthesis of unsymmetrical thiosulfonates. The reactions occur at room temperature and provide good-to-excellent yields of the desired products.