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Metal ions can have beneficial effects on photoinduced electron transfer. Merging such metal-ion-coupled electron transfer (MCET) with consecutive photoinduced electron transfer (conPET) enables the one-electron reduction of chlorobenzene with blue light in the presence of diisopropylethylamine as an electron donor. The presence of the metal ions extends the substrate scope of the photoredox catalysis to extreme reduction potentials (beyond −3 V vs. SCE). [ABSTRACT FROM AUTHOR]

The cyanamide-functionalised carbon nitride (NCN-CN x) can be employed as a photo-redox catalyst for the light-induced sulfonylation of alkenes with sulfinate salts, attaining product yields twice those obtained with the non-functionalised counterpart and comparable to those achieved with the benchmark homogeneous photocatalyst Eosin Y. NCN-CN x as a heterogeneous photocatalyst is easily isolatable and can be re-used for this reaction for over three cycles. This photocatalytic reaction can proceed with various sulfinates (aryl-, alkyl- and thiophene-based) and alkenes with electron-donating and -withdrawing groups, obtaining good to excellent product yields. A reductive quenching route was determined to be the likely mechanism for this photocatalyst. [ABSTRACT FROM AUTHOR]

Heteroaromatische Sulfoxide sind häufig in Naturstoffen, Pharmazeutika, Katalysatoren und Werkstoffen zu finden. Wir beschreiben eine metallfreie, durch sichtbares Licht beschleunigte Synthese von heteroaromatischen Sulfoxiden aus Sulfinamiden und Peroxodisulfat. Die Reaktion verläuft bei Raumtemperatur unter Bestrahlung mit blauem Licht und ermöglicht die C-H-Sulfinylierung von elektronenreichen Heteroaromaten wie Pyrrol und Indol. Basierend auf der Substratbreite, der Substitutionsselektivität und Konkurrenzexperimenten mit verschiedenen Nukleophilen schlagen wir als Mechanismus eine elektrophile aromatische Substitution vor. [ABSTRACT FROM AUTHOR]

Heteroaromatic sulfoxides are a frequent structural motif in natural products, drugs, catalysts, and materials. We report a metal-free visible-light-accelerated synthesis of heteroaromatic sulfoxides from sulfinamides and peroxodisulfate. The reaction proceeds at room temperature with blue-light irradiation and allows the C−H sulfinylation of electron-rich heteroarenes, such as pyrroles and indoles. An electrophilic aromatic substitution mechanism is proposed based on the substrate scope, substitution selectivity, and competition experiments with different nucleophiles. [ABSTRACT FROM AUTHOR]

We report a one-step procedure for the preparation of N-(2-pyrrole)-sulfonamides from sulfonamides and pyrroles. The reaction uses visible light, an acridinium dye as photocatalyst and oxygen as the terminal oxidant for the oxidative C–N bond formation; structures of several reaction products were confirmed by X-ray structure analysis. The reaction is selective for pyrroles, due to the available oxidation power of the photocatalyst and the required stability of the carbocation intermediate under the reaction conditions. [ABSTRACT FROM AUTHOR]

Ions and radicals of the same kind differ by one electron only. The oxidation of many stable inorganic anions yields their corresponding highly reactive radicals, and visible light excitable photocatalysts can provide the required oxidation potential for this transformation. Air oxygen serves as the terminal oxidant, or cheap sacrificial oxidants are used, providing a very practical approach for generating reactive inorganic radicals for organic synthesis. We discuss in this perspective several recently reported examples: Nitrate radicals are obtained by one-electron photooxidation of nitrate anions and are very reactive toward organic molecules. The photooxidation of sulfinate salts yields the much more stable sulfone radicals, which smoothly add to double bonds. A two-electron oxidation of chloride anions to electrophilic chlorine species reacting with arenes in aromatic substitutions extends the method beyond radical reactions. The chloride anion oxidation proceeds via photocatalytically generated peracidic acid as the oxidation reagent. Although the number of reported examples of photocatalytically generated inorganic radical intermediates for organic synthesis is still small, future extension of the concept to other inorganic ions as radical precursors is a clear perspective. [ABSTRACT FROM AUTHOR]

Alkyl- and aryl vinyl sulfones were obtained by eosin Y (EY)-mediated visible-light photooxidation of sulfinate salts and the reaction of the resulting S-centered radicals with alkenes. Optimized reaction conditions, the sulfinate and alkene scope, and X-ray structural analyses of several reaction products are provided. A detailed spectroscopic study explains the reaction mechanism, which proceeds through the EY radical cation as key intermediate oxidizing the sulfinate salts. [ABSTRACT FROM AUTHOR]

Visible light and eosin Y catalyze the synthesis of vinyl sulfones from aryl sulfinates and alkenes by a photoredox process. The reaction scope is broad in aryl sulfinates and alkenes and the general and simple procedure provides a metal-free alternative for the synthesis of synthetically valuable vinyl sulfones. [ABSTRACT FROM AUTHOR]

Alkyl- and aryl vinyl sulfones are obtained by eosin Y (EY)-mediated visible-light photooxidation of sulfinate salts and reaction of the resulting S-centered radicals with alkenes. [ABSTRACT FROM AUTHOR]

Review: 49 refs + subrefs. [ABSTRACT FROM AUTHOR]

An abstract of the article "Visible Light-Mediated Metal-Free Synthesis of Vinyl Sulfones from Aryl Sulfinates" by A. U. Meyer and colleagues is presented.