Silver-Promoted Decarboxylative Sulfonylation of Aromatic Carboxylic Acids with Sodium Sulfinates

Palladium-catalyzed denitrative N-arylation of nitroarenes with pyrroles, indoles, and carbazole

We have developed an efficient palladium-catalyzed denitrative N-arylation via cross-coupling of N–H heteroarenes with nitroarenes, one of the most inexpensive and fundamental feedstocks in the chemical industry. A variety of...

Atom-Economical, Catalyst-Free Hydrosulfonation of Densely Functionalized Alkenes: Access to Oxindole Containing Sulfones

An atom-economical hydrosulfonation of densely functionalized alkenes under catalyst-free conditions is described. Alkenes possessing hydroxy-oxindole moiety underwent hydrosulfonation on treatment with arylsulfinic acids in green media to afford the resulting...

Chan-Lam-Type C-S Coupling Reaction by Sodium Aryl Sulfinates and Organoboron Compounds

A Chan-Lam-type C-S coupling reaction using sodium aryl sulfinates has been developed to provide diaryl thioethers in up to 92% yields in the presence of a copper catalyst and potassium sulfite. Both electron-rich and electron-poor sodium aryl sulfinates and diverse organoboron compounds were tolerated for the synthesis of aryl and heteroaryl thioethers and dithioethers. The mechanistic study suggested that potassium sulfite was involved in the deoxygenation of sulfinate through a radical process.

Recent developments in decarboxylative C(aryl)-X bond formation from (hetero)aryl carboxylic acids

Decarboxylative coupling reactions using readily available (hetero)aryl carboxylic acids are a highly efficient approach for the formation of new C-C and C-X bonds. These decarboxylative coupling reactions eliminate CO2 as a by-product, resulting in a greener and environmentally more benign approach than conventional coupling reactions. In this review, we summarize the recent developments in ipso-decarboxylative C-X (X = O/N/halo/S/Se/P/CN) bond formations using (hetero)aryl carboxylic acids. Furthermore, we highlight the current limitations and future research opportunities of aryl-decarboxylative coupling reactions.

Practical Electro-Oxidative Sulfonylation of Phenols with Sodium Arenesulfinates Generating Arylsulfonate Esters

A practical and sustainable synthesis of arylsulfonate esters has been developed through electro-oxidation. This reaction employed the stable and readily available phenols and sodium arenesulfinates as the starting materials and took place under mild reaction conditions without additional oxidants. A wide range of arylsulfonate esters including those bearing functional groups were produced in good to excellent yields. This reaction could also be conducted at a gram scale without a decrease of reaction efficiency. Those results well demonstrated the potential synthetic value of this reaction in organic synthesis.

Synthesis and applications of sodium sulfinates (RSO2Na): a powerful building block for the synthesis of organosulfur compounds

This review highlights the preparation of sodium sulfinates (RSO2Na) and their multifaceted synthetic applications. Substantial progress has been made over the last decade in the utilization of sodium sulfinates emerging as sulfonylating, sulfenylating or sulfinylating reagents, depending on reaction conditions. Sodium sulfinates act as versatile building blocks for preparing many valuable organosulfur compounds through S-S, N-S, and C-S bond-forming reactions. Remarkable advancement has been made in synthesizing thiosulfonates, sulfonamides, sulfides, and sulfones, including vinyl sulfones, allyl sulfones, and β-keto sulfones. The significant achievement of developing sulfonyl radical-triggered ring-closing sulfonylation and multicomponent reactions is also thoroughly discussed. Of note, the most promising site-selective C-H sulfonylation, photoredox catalytic transformations and electrochemical synthesis of sodium sulfinates are also demonstrated. Holistically, this review provides a unique and comprehensive overview of sodium sulfinates, which summarizes 355 core references up to March 2020. The chemistry of sodium sulfinate salts is divided into several sections based on the classes of sulfur-containing compounds with some critical mechanistic insights that are also disclosed.

Electrochemical study of 4-chloroaniline in a water/acetonitrile mixture. A new method for the synthesis of 4-chloro-2-(phenylsulfonyl)aniline and N-(4-chlorophenyl)benzenesulfonamide

The electrochemical oxidation of 4-chloroaniline as a model compound in a water/acetonitrile mixture was investigated by cyclic voltammetry and differential pulse voltammetry. It was established that one-electron oxidation of 4-chloroaniline followed by disproportionation reaction affords unstable (4-iminocyclohexa-2,5-dien-1-ylidene)chloronium. In water/acetonitrile mixtures and in the absence of nucleophiles, the most likely reaction on produced chloronium is hydrolysis and p-quinoneimine formation. The electrochemical oxidation of 4-chloroaniline in the presence of arylsulfinic acids was also investigated in a water/acetonitrile mixture at a glassy carbon electrode. It was established that under these conditions, the anodically generated chloronium reacts with benzenesulfinic acid to produce the corresponding diaryl sulfone and N-phenylbenzenesulfonamide derivatives. In addition, Gaussian 09W was applied for prediction of the possible product by the calculation of natural charge, LUMO orbital energies and thermodynamic stability of intermediates and products.

Electrochemical oxidation pathway of p-chloroaniline (PCA) in the presence of benzenesulfinic acid (BSA).

Visible-light-induced anti-Markovnikov hydrosulfonation of styrene derivatives

A visible-light-induced anti-Morkovnikov hydrosulfonation reaction of styrene derivatives with sodium sulfinates has been developed, featuring mild reaction conditions, good functional-group tolerance, good yields and high regioselectivity.