Single-Electron Transfer from Dimsyl Anion in the Alkylation of Phenols

Facile Cleavage of Activated Ketones: An Access to Thioethers via In Situ Generation of Anhydrides by Pummerer-Type Rearrangement

Herein, we report an oxygen insertion in activated ketones from simple inorganic carbonates for the synthesis of symmetric aromatic anhydrides. For the first time, Li2CO3 acts as an oxygen source and the in situ generated symmetric aromatic anhydrides undergo Pummerer-type rearrangement to access α-benzoyloxy-thioethers. Attractively, this protocol occurs under metal-, ligand-, and oxidant-free conditions and is compatible with a wide range of substrates. Control experiments reveal the reaction pathway.

Selectfluor-Promoted Reactions of Aryl Methyl Ketones with Dimethyl Sulfoxide to Give 2,5-Diacylthiophenes and β-Acyl Allylic Methylsulfones

In this paper, a convenient synthesis of 2,5-diacylthiophenes and β-acyl allylic methylsulfones from aryl methyl ketones with dimethyl sulfoxide (DMSO) through Selectfluor-promoted cascade cyclization and cross-coupling reactions by simple solvent modification is described. This method enables the formation of new C-C and C-S bonds via the selection of different solvent ratios, in which DMSO molecules as synthons can be selectively introduced into methyl ketones. The features of this transformation include readily available starting materials, excellent chemoselectivity, and good functional group tolerance.

Coupling of thiols and aromatic halides promoted by diboron derived super electron donors

We have proven that pyridine-boryl complexes can be used as superelectron donors to promote the coupling of thiols and aromatic halides through a S_RN1 mechanism. The reaction is efficient for a broad substrate scope, tolerating heterocycles including pyridines, enolizable or reducible functional groups. The method has been applied to intermediates in drug synthesis as well as interesting functionalized polythioethers through a controlled and consecutive intramolecular electron transfer process.

Dimsyl Anion Enables Visible‐Light‐Promoted Charge Transfer in Cross‐Coupling Reactions of Aryl Halides

A methodology is reported for visible-light-promoted synthesis of unsymmetrical chalcogenides enabled by dimsyl anion in the absence of transition-metals or photoredox catalysts. The cross-coupling reaction between aryl halides and diaryl dichalcogenides proceeds with electron-rich, electron-poor, and heteroaromatic moieties. Mechanistic investigations using UV-Vis spectroscopy, time-dependent density functional theory (TD-DFT) calculations, and control reactions suggest that dimsyl anion forms an electron-donor-acceptor (EDA) complex capable of absorbing blue light, leading to a charge transfer responsible for generation of aryl radicals from aryl halides. This previously unreported mechanistic pathway may be applied to other light-induced transformations performed in DMSO in the presence of bases and aryl halides.

Transition-metal free synthesis of N-aryl carbazoles and their extended analogs

Herein, we describe a facile synthesis of N-arylated carbazoles via ladderization of fluorinated oligophenylenes. The reaction consists of two subsequent nucleophilic substitutions triggered by an electronic transfer from dimsyl anions. The reaction allows the effective one-pot formation of at least six C-N bonds with pronounced selectivity to the C-F bond placement.

Radical Anion Promoted Chemoselective Cleavage of Csp2-S Bond Enables Formal Cross-Coupling of Aryl Methyl Sulfones with Alcohols

A novel formal cross-coupling of aryl methyl sulfones and alcohols affording alkyl aryl ethers via an S_RN1 pathway is developed. Two marketed antitubercular drugs were efficiently prepared employing this approach as the key step. A dimsyl-anion initiated radical chain process was revealed as the major pathway. DFT calculations indicate that the formation of a radical anion via nucleophilic addition of alkoxide to the aryl radical is the key step in determining the observed chemoselectivity.

NBS-activated cross-dehydrogenative esterification of carboxylic acids with DMSO

A convenient and versatile cross-dehydrogenative esterification of carboxylic acids with DMSO for preparing (methylsulfinyl)methyl esters has been developed in the presence of N-bromosuccinimide.