Visible-Light Photoredox-Catalyzed Aminosulfonylation of Diaryliodonium Salts with Sulfur Dioxide and Hydrazines

Synthesis of β-Sulfonyl Amides through a Multicomponent Reaction with the Insertion of Sulfur Dioxide under Visible Light Irradiation

A multicomponent reaction of styrenes, aryldiazonium tetrafluoroborates, sulfur dioxide, nitriles, and water in the presence of a photocatalyst at room temperature is performed. This vicinal aminosulfonylation of styrenes with the insertion of sulfur dioxide under visible light irradiation proceeds efficiently with excellent chemoselectivity, giving rise to the corresponding β-sulfonyl amides in moderate to good yields.

Thiourea dioxide as a source of sulfonyl groups: photoredox generation of sulfones and sulfonamides from heteroaryl/aryl halides

Thiourea dioxide as the source of sulfonyl groups for the efficient synthesis of heteroaryl sulfones and sulfonamides from heteroaryl halides under visible light irradiation is reported. This transformation proceeds smoothly via heteroaryl sulfinate intermediates, which can be trapped in situ by various electrophiles. A broad reaction scope is demonstrated, especially for the electron-deficient heteroaryl halides. Mechanistic studies show that the radical coupling of the heteroaryl radical and sulfur dioxide radical anion may be the key step during the reaction process, as supported by EPR spectroscopy and DFT calculations.

Photoredox-catalyzed sulfonylation of alkyl iodides, sulfur dioxide, and electron-deficient alkenes

A photoredox-catalyzed sulfonylation of alkyl iodides, sulfur dioxide, and electron-deficient alkenes under mild conditions is achieved. This reaction proceeds through alkyl radicals formed in situ from alkyl iodides under visible light irradiation in the presence of a photoredox catalyst. The alkyl radical intermediates would react with sulfur dioxide leading to alkylsulfonyl radicals, which would be trapped by electron-deficient alkenes giving rise to alkyl sulfones. Various functional groups including nitro, halo, acetyl, sufonyl, and pyridinyl are all tolerated under the photoredox conditions.

Synthesis of 3-(Methylsulfonyl)benzo[ b]thiophenes from Methyl(2-alkynylphenyl)sulfanes and Sodium Metabisulfite via a Radical Relay Strategy

A radical relay strategy for the generation of 3-(methylsulfonyl)benzo[ b]thiophenes through a reaction of methyl(2-alkynylphenyl)sulfanes with sodium metabisulfite in the presence of a photocatalyst under visible light irradiation is developed. This photoinduced sulfonylation proceeds efficiently under mild conditions by using a catalytic amount of sodium methylsulfinate as an initiator. During the reaction process, the methyl radical generated in situ is the key intermediate, which undergoes a radical relay with the combination of sulfur dioxide to afford methylsulfonyl-containing compounds.

Inorganic sulfites as the sulfur dioxide surrogates in sulfonylation reactions

Recent advances in the sulfonylation reactions by using inorganic sulfites as the source of sulfonyl group are reported. The approaches employing inorganic sulfites as sulfur dioxide surrogates are attractive and promising for the synthesis of sulfonyl compounds since inorganic sulfites are abundant, easily available and cheap. The transformations using inorganic sulfites as the source of sulfonyl group work efficiently, providing diverse sulfonyl compounds including sulfones and sulfonamides. The sulfonylation reactions can be performed under transition metal catalysis or through radical processes under catalyst- and additive-free conditions. In some cases, a photocatalyst is employed under visible-light irradiation to facilitate the transformation. For the sulfur dioxide surrogate of inorganic sulfites, potassium metabisulfite or sodium metabisulfite has been broadly used in various transformations. However, the reactivities of inorganic sulfites in organic reactions still need to be explored.

Visible-light mediated sulfonylation of thiols via insertion of sulfur dioxide

Photocatalytically generated sulfenyl radicals were coupled with arylsulfonyl radicals at room temperature for accessing unsymmetrical organic thiosulfonates.

Cu(OTf)2-mediated C(sp2)–H arylsulfonylation of enamides via the insertion of sulfur dioxide

A stereoselective Cu(OTf)₂-mediated C(sp²)–H sulfonylation of enamides with arylsulfonyl radicals generated in situ from DABSO and diazonium salts is developed.

Visible-light-promoted organic dye-catalyzed sulfidation and phosphorylation of arylhydrazines toward aromatic sulfides and diarylphosphoryl hydrazides

Visible-light-promoted sulfidation and phosphorylation of arylhydrazines for the synthesis of aromatic sulfides and diarylphosphoryl hydrazides were developed using the organic dyes rose bengal and Na₂-eosin Y as photocatalysts, respectively.

Photoredox-catalyzed hydrosulfonylation reaction of electron-deficient alkenes with substituted Hantzsch esters and sulfur dioxide

A sulfonylation reaction of 4-substituted Hantzsch esters, DABCO·(SO₂)₂, and electron-deficient alkenes at room temperature in the presence of photoredox catalysis under visible light irradiation is described.

Manganese(iii) acetate-mediated direct C(sp2)–H-sulfonylation of enamides with sodium and lithium sulfinates

A Mn(OAc)₃ mediated oxidative C(sp²)–H sulfonylation of enamides and encarbamates with sodium and lithium sulfinates is reported.

Photoinduced synthesis of allylic sulfones using potassium metabisulfite as the source of sulfur dioxide

Synthesis of allylic sulfones through a photoinduced three-component reaction of aryl/alkyl halides, potassium metabisulfite, and allylic bromides under ultraviolet irradiation at room temperature is developed. Diverse allylic sulfones are generated in moderate to good yields.

An unexpected reaction of aryldiazonium tetrafluoroborates, sodium metabisulfite, and thiourea under photoinduced conditions

A photoinduced synthesis of S-aryl thiosulfonates through a three-component reaction of aryldiazonium tetrafluoroborates, sodium metabisulfite, and thiourea is achieved. In this transformation, a radical coupling pathway is proposed.

Electron diffraction tomography and X-ray powder diffraction on photoredox catalyst PDI

The crystal structure of photoredox catalyst PDI-iPr was determined by a combination of electron diffraction tomography and XRPD.

Photoredox-catalyzed sulfonylation of alkenylcyclobutanols with the insertion of sulfur dioxide through semipinacol rearrangement

A photoredox-catalyzed sulfonylation of alkenylcyclobutanols with the insertion of sulfur dioxide through semipinacol rearrangement under visible light irradiation is developed.

Substituted Hantzsch esters as radical reservoirs with the insertion of sulfur dioxide under photoredox catalysis

A three-component reaction between 4-substituted Hantzsch esters, DABCO·(SO₂)₂, and vinyl azides in the presence of photoredox catalysts under visible light irradiation is developed. A range of (Z)-2-(alkylsulfonyl)-1-arylethen-1-amines is obtained in moderate to good yields with good regioselectivity and stereoselectivity.

Direct Copper-Catalyzed Three-Component Synthesis of Sulfonamides

First introduced into medicines in the 1930s, the sulfonamide functional group continues to be present in a wide range of contemporary pharmaceuticals and agrochemicals. Despite their popularity in the design of modern bioactive molecules, the underpinning methods for sulfonamide synthesis are essentially unchanged since their introduction, and rely on the use of starting materials with preinstalled sulfur-functionality. Herein we report a direct single-step synthesis of sulfonamides that combines two of the largest monomer sets available in discovery chemistry, (hetero)aryl boronic acids and amines, along with sulfur dioxide, using a Cu(II) catalyst, to deliver a broad range of sulfonamides. Sulfur dioxide is provided by the surrogate reagent DABSO. The reaction tolerates broad variation in both coupling partners, including aryl, heteroaryl and alkenyl boronic acids, as well as cyclic and acyclic alkyl secondary amines, and primary anilines. We validate the method by showing that a variety of drugs, and drug-fragments, can be incorporated into the process.

Visible-light-induced multicomponent cascade cycloaddition involving N-propargyl aromatic amines, diaryliodonium salts and sulfur dioxide: rapid access to 3-arylsulfonylquinolines

A visible-light-induced, Eosin Y catalyzed three-component synthesis of 3-arylsulfonylquinoline derivatives through N-propargyl aromatic amines, diaryliodonium salts and sulfur dioxide has been discovered. This transformation represents an efficient and attractive method for the straightforward synthesis of 3-arylsulfonylquinoline derivatives via the formation of C-S bonds and quinolines in one step. In addition, it exhibits good substrate scope and functional group tolerance. The use of easy-to-handle diaryliodonium salts, sulfur dioxide sources and the cheap photocatalyst Eosin Y together with facile operation at room temperature makes this protocol very practical.

Cross-Coupling of Sodium Sulfinates with Aryl, Heteroaryl, and Vinyl Halides by Nickel/Photoredox Dual Catalysis

An efficient photoredox/nickel catalyzed sulfonylation reaction of aryl, heteroaryl, and vinyl halides has been achieved for the first time. This newly developed sulfonylation protocol provides a versatile method for the synthesis of diverse aromatic sulfones at room temperature and shows excellent functional group tolerance. The electrophilic coupling partners are not limited to aryl, heteroaryl, and vinyl bromides and iodides, but also includes less reactive aryl chlorides as suitable substrates for this transformation.

Photocatalytic formation of carbon-sulfur bonds

This review summarizes recent developments in photocatalyzed carbon-sulfur bond formation. General concepts, synthetic strategies and the substrate scope of reactions yielding thiols, disulfides, sulfoxides, sulfones and other organosulfur compounds are discussed together with the proposed mechanistic pathways.

Insertion of sulfur dioxide via a radical process: an efficient route to sulfonyl compounds

This review is focused on the recent advances in the chemistry of sulfur dioxide fixation through a radical process. Diverse sulfonyl compounds can be obtained efficiently under mild conditions.

Thiosulfonylation of alkenes with the insertion of sulfur dioxide under non-metallic conditions

A three-component reaction of 1-(2-allylaryl)thioureas, sulfur dioxide, and aryldiazonium tetrafluoroborates under mild conditions is realized, leading to sulfonated [3,1]-benzothiazepines in good yields. High efficiency is observed for this non-metallic transformation.

Photoinduced synthesis of (E)-vinyl sulfones through the insertion of sulfur dioxide

Under visible light irradiation, a three-component reaction of potassium alkyltrifluoroborates, sulfur dioxide and alkynes with the assistance of photocatalysis and in the presence of copper(ii) triflate is described. This transformation affords (E)-vinyl sulfones efficiently with excellent regioselectivity and stereoselectivity under mild conditions.

Recent advances in the sulfonylation of alkenes with the insertion of sulfur dioxide via radical reactions

Recent advances in the sulfonylation of alkenes via the insertion of sulfur dioxide are summarized. Two strategies for the sulfonylation of alkenes with the insertion of sulfur dioxide have been developed.

Recent advances in the sulfonylation of C–H bonds with the insertion of sulfur dioxide

Recent advances in the sulfonylation of C–H bonds with the insertion of sulfur dioxide are summarized. C–H bond sulfonylation under transition metal catalysis or through a radical process has been developed. In some cases, the sulfonylation can be performed under catalyst- and additive-free conditions, or can be facilitated by visible light irradiation. The efficiency is also studied by merging the radical process and metal catalysis.

C–H bond sulfonylation of anilines with the insertion of sulfur dioxide under metal-free conditions

2-Sulfonylanilines are generated in moderate to good yields through a three-component reaction of anilines, DABCO·(SO₂)₂, and aryldiazonium tetrafluoroborates under mild conditions. No metal catalysts or additives are needed for this transformation.

Photocatalytic acylarylation of unactivated alkenes with diaryliodonium salts toward indanones and related compounds

A photocatalytic acylarylation of unactivated alkenes using diaryliodonium salts is described, giving 2-benzyl indanones and related compounds in promising yields with excellent diastereoselectivity.

Benzylic C(sp3)–H bond sulfonylation of 4-methylphenols with the insertion of sulfur dioxide under photocatalysis

Sulfonylation of the benzylic C–H bond is developed through a three-component reaction of aryldiazonium tetrafluoroborates, 4-methylphenols and sodium metabisulfite (Na₂S₂O₅). The inorganic sulfite of sodium metabisulfite is used as the SO₂ surrogate.

Synthesis of 6-(sulfonylmethyl)phenanthridines through a reaction of aryldiazonium tetrafluoroborates, sulfur dioxide, and vinyl azides

Synthesis of 6-(sulfonylmethyl)phenanthridines through a three-component reaction of aryldiazonium tetrafluoroborates, a sulfur dioxide surrogate of DABCO·(SO₂)₂, and vinyl azides under metal- and additive-free conditions is achieved.

Intramolecular oxysulfonylation of alkenes with the insertion of sulfur dioxide under photocatalysis

Intramolecular oxysulfonylation of alkenes with the insertion of sulfur dioxide promoted by visible light is developed, leading to sulfonated tetrahydrofurans and related compounds in moderate to good yields.

A copper-catalyzed sulfonylative C–H bond functionalization from sulfur dioxide and aryldiazonium tetrafluoroborates

Sulfonylative C–H bond functionalization through a copper-catalyzed three-component reaction of 8-aminoquinoline amides, DABCO·(SO₂)₂ and aryldiazonium tetrafluoroborates is developed. Excellent selectivity in the para-position is observed.

Generation of sulfonated 1-isoindolinones through a multicomponent reaction with the insertion of sulfur dioxide

A four-component reaction of 2-vinylbenzoic acids, aryldiazonium tetrafluoroborates, sulfur dioxide, and nitriles under photocatalysis in the presence of visible light is developed, leading to sulfonated 1-isoindolinones in moderate to good yields.