Thiosulfonates are accessed by oxidation of feed-stock thiols using either DMP in DCM or IBX in MeCN at rt (~30 degree C). The protocol gives access to a variety of thiosulfonates in good to excellent yields from both aromatic and aliphatic thiols. The reaction with DMP is found to be better than IBX in terms of reaction rate and conversion, whereas the oxidation with DMP requires lower equivalent than IBX. Benzyl thiols are however found to follow a different reaction pathway when treated with DMP; O-benzyl esters of o-iodobenzoates were isolated. The 1H NMR spectroscopic monitoring studies for the IBX-mediated oxidation of thiol found disulfide as an initial intermediate, which is proposed to undergoes a cascade of oxidations to produce thiosulfonate
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.
The reaction between aryl olefins and thiols in the presence of Oxone in toluene-water (9:1, v/v) affords β-hydroxy-2-arylethyl aryl sulfides smoothly by interception of the intermediary thiyl radicals with aryl...
Visible light-mediated facile synthesis of heteroarenes,
namely,
isoquinolines, benzothiazoles, and quinazolines, is demonstrated by
employing isocyanides and inexpensive acyl peroxides. It is shown
for the first time that singlet-excited isocyanides decompose acyl
peroxides into aryl/alkyl radicals. The latter attack isocyanides,
yielding imidoyl radicals that subsequently cyclize to afford heteroarene
products. The protocol involving radical cascade reactions obviates
the requirement of any external photocatalyst, oxidant, additive,
and base.
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