1,2,4,5-Tetrathiane - 1. Synthesen und Reaktionen

Franek, W.

doi:10.1080/01961779108048755

Cited by 11 publications

(1 citation statement)

References 54 publications

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“…The developed protocols of sulfurization in the presence of fluoride anion can be of interest not only for the synthesis of sulfur-rich heterocycles, such as 1,2,4-trithiolanes [ 28 ], 1,2,4,5-tetrathianes [ 35 , 36 ] or 1,2,3,5,6-pentathiepanes, but also for the preparation of sulfur-rich polymers starting with alkyl- [ 37 , 38 ] or aryl [ 39 ] substituted thiiranes. In the present work, fluoride anion was shown to act as an alternative, nucleophilic catalyst and can replace smelly and unstable sodium (or potassium) thiophenolate in the activation of elemental sulfur in reactions with thiiranes.…”

Section: Discussionmentioning

confidence: 99%

The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

et al. 2021

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Fluoride anion was demonstrated as a superior activator of elemental sulfur (S8) to perform sulfurization of thioketones leading to diverse sulfur-rich heterocycles. Due to solubility problems, reactions must be carried out either in THF using tetrabutylammonium fluoride (TBAF) or in DMF using cesium fluoride (CsF), respectively. The reactive sulfurizing reagents are in situ generated, nucleophilic fluoropolysulfide anions FS(8−x)−, which react with the C=S bond according to the carbophilic addition mode. Dithiiranes formed thereby, existing in an equilibrium with the ring-opened form (diradicals/zwitterions) are key-intermediates, which undergo either a step-wise dimerization to afford 1,2,4,5-tetrathianes or an intramolecular insertion, leading in the case of thioxo derivatives of 2,2,4,4-tetramethylcyclobutane-1,3-dione to ring enlarged products. In reactions catalyzed by TBAF, water bounded to fluoride anion via H-bridges and forming thereby its stable hydrates is involved in secondary reactions leading, e.g., in the case of 2,2,4,4-tetramethyl-3-thioxocyclobutanone to the formation of some unexpected products such as the ring enlarged dithiolactone and ring-opened dithiocarboxylate. In contrast to thioketones, the fluoride anion catalyzed sulfurization of their α,β-unsaturated analogues, i.e., thiochalcones is slow and inefficient. However, an alternative protocol with triphenylphosphine (PPh3) applied as a catalyst, offers an attractive approach to the synthesis of 3H-1,2-dithioles via 1,5-dipolar electrocyclization of the in situ-generated α,β-unsaturated thiocabonyl S-sulfides. All reactions occur under mild conditions and can be considered as attractive methods for the preparation of sulfur rich heterocycles with diverse ring-size.

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Section: Discussionmentioning

confidence: 99%

The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

et al. 2021

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ChemInform Abstract: 1,2,4,5‐Tetrathianes. Part 1. Syntheses and Reactions

Franek¹

1991

ChemInform

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Bildung von 1,2,4‐Trithiolanen in Dreikomponenten‐Gemischen aus Phenyl‐azid, aromatischen Thioketonen und 2,2,4,4‐Tetramethylcyclobutanthionen: Eine Schwefel‐Transfer‐Reaktion unter Bildung von ‘Thiocarbonylthiolaten’ ((Alkylidensulfonio)thiolaten) als reaktive Zwischenstufen

Mlostoń

Heimgartner

1995

Helvetica Chimica Acta

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The reaction of PhN, and aromatic thioketoiies 18 (two-component reaction) at 80" yields only the corresponding imines 22, S, and N2. Under similar conditions, in the prescnce of sterically crowded 2,2,4,4-tetramethylcyclobutanethiones 19 (three-component reaction), 1,2,4-trithiolanes of type 20 are formed in good yields in addition to iinines 22 (Scheme 4). In case of 19a and 19c (X = CO, CS), the symmetrical trithiolanes 21a and 21b, respectively, are also isolated. With 4,4-dimethyl-2-phenyl-l,3-thiazole-5(4H)-thione (24) instead of aromatic thioketone 18, imine 25, trithiolane 21a, and 1,4,2-dithiazolidine 26 are formed (Scheme 5). A reaction mechanism for the formation of 1,2,4-trithiolanes 20 and 21, including an S-transfer to generate 'thiocarbonyl-thiolates' 2b and/or 2c and 1,3-dipolar cycloaddition with a thioketone, is proposed in Scheme 7.

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1,2,4,5-Tetrathiane - 1. Synthesen und Reaktionen

Cited by 11 publications

References 54 publications

The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

ChemInform Abstract: 1,2,4,5‐Tetrathianes. Part 1. Syntheses and Reactions

Bildung von 1,2,4‐Trithiolanen in Dreikomponenten‐Gemischen aus Phenyl‐azid, aromatischen Thioketonen und 2,2,4,4‐Tetramethylcyclobutanthionen: Eine Schwefel‐Transfer‐Reaktion unter Bildung von ‘Thiocarbonylthiolaten’ ((Alkylidensulfonio)thiolaten) als reaktive Zwischenstufen

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