1,2-Fluorosulfenylation of unactivated alkenes with thiols and a fluoride source promoted by bromodimethylsulfonium bromide

A practical method that enables the fluorosulfenylation of unactivated alkenes processed directly with thiols and fluoride salts is presented. Good to excellent efficiencies and functional group tolerance are observed for both alkene substrates and thiols. The procedure also allows the use of gaseous ethylene as a two-carbon building block for β-fluoro thioether products.

Controlling Selectivity in Shuttle Hetero-difunctionalization Reactions: Electrochemical Transfer Halo-thiolation of Alkynes

Shuttle hetero-difunctionalization reaction, in which two chemically distinct functional groups are transferred between two molecules, has long been an unmet goal due to the daunting challenges in controlling the chemo-, regio-, and stereoselectivity. Herein, we disclose an electrochemistry enabled shuttle reaction (e-shuttle) to selectively transfer one RS^- and one X^- group between β-halosulfides and unsaturated hydrocarbons via a consecutive paired electrolysis mechanism. The preferential anodic oxidation of one anion over the other, which is controlled by their distinct redox potentials, plays a pivotal role in controlling the high chemoselectivity of the process. This easily scalable methodology enables the construction of a myriad of densely functionalized β-halo alkenyl sulfides in unprecedented chemo-, regio-, and stereoselectivity using benign surrogates, e.g., 2-bromoethyl sulfide, avoiding the handling of corrosive and oxidative RS-Br reagents. In a broader context, these results open up new strategies for selective shuttle difunctionalization reactions.

Rapid access to organic triflates based on flash generation of unstable sulfonium triflates in flow

Flash (extremely fast) electrochemical generation of unstable arylbis(arylthio)sulfonium triflates [ArS(ArSSAr)]⁺ [OTf]^- that are unsuitable for accumulation in batch processes was achieved within 10 s in a divided-type flow electrochemcial reactor, enabling one-flow access to vinyl triflates, short-lived oxocarbenium triflates and glycosyl triflates.

Electrochemical fluorosulfonylation of styrenes

An environmentally friendly and efficient electrochemical fluorosulfonylation of styrenes has been developed. With the use of sulfonylhydrazides and triethylamine trihydrofluoride, a diverse array of β-fluorosulfones could be readily obtained. This reaction features mild conditions and a broad substrate scope, which could also be conveniently extended to a gram-scale preparation.

Practical fluorothiolation and difluorothiolation of alkenes using pyridine-HF and N-thiosuccinimides

Fluorothiolation and difluorothiolation of alkenes using pyridine-HF and N-thiosuccinimides.

Oxo-Thiolation of Cationically Polymerizable Alkenes Using Flow Microreactors

The present study describes the cationic oxo-thiolation of polymerizable alkenes by using highly reactive cationic species generated by anodic oxidation. These highly reactive cations were able to activate alkenes before their polymerization. Fast mixing in flow microreactors effectively controlled chemoselectivity, enabling higher reaction temperatures.

Electrochemical Flash Fluorination and Radiofluorination

A new method for rapid late-stage fluorination using the cation pool technique is presented. Fluorination and no-carrier-added radiofluorination of methyl (phenylthio) acetate, methyl 2-(methylthio) acetate, and methyl 2-(ethylthio) acetate were performed. The carbocations formed through electrochemical oxidation were stabilized by using a divided electrochemical cell and 2,2,2-trifluoroethanol (TFE) as the solvent at -20 °C. At the end of electrolysis, either stable-isotope [¹⁹F]fluoride or no-carrier-added radioactive [¹⁸F]fluoride was added to the reaction mixture to form the fluorinated or radiofluorinated product.

Electrochemical strategies for C-H functionalization and C-N bond formation

Conventional methods for carrying out carbon-hydrogen functionalization and carbon-nitrogen bond formation are typically conducted at elevated temperatures, and rely on expensive catalysts as well as the use of stoichiometric, and perhaps toxic, oxidants. In this regard, electrochemical synthesis has recently been recognized as a sustainable and scalable strategy for the construction of challenging carbon-carbon and carbon-heteroatom bonds. Here, electrosynthesis has proven to be an environmentally benign, highly effective and versatile platform for achieving a wide range of nonclassical bond disconnections via generation of radical intermediates under mild reaction conditions. This review provides an overview on the use of anodic electrochemical methods for expediting the development of carbon-hydrogen functionalization and carbon-nitrogen bond formation strategies. Emphasis is placed on methodology development and mechanistic insight and aims to provide inspiration for future synthetic applications in the field of electrosynthesis.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.

Electrogenerated Cationic Reactive Intermediates: The Pool Method and Further Advances

Electrochemistry serves as a powerful method for generating reactive intermediates, such as organic cations. In general, there are two ways to use reactive intermediates for chemical reactions: (1) generation in the presence of a reaction partner and (2) generation in the absence of a reaction partner with accumulation in solution as a "pool" followed by reaction with a subsequently added reaction partner. The former approach is more popular because reactive intermediates are usually short-lived transient species, but the latter method is more flexible and versatile. This review focuses on the latter approach and provides a concise overview of the current methods for the generation and accumulation of cationic reactive intermediates as a pool using modern techniques of electrochemistry and their reactions with subsequently added nucleophilic reaction partners.

Low temperature in situ Raman spectroscopy of an electro-generated arylbis(arylthio)sulfonium ion

Low temperature in situ Raman spectroscopy detects reactive intermediate cations generated by the electrochemical oxidation in organic chemistry.

Ring-opening hydrofluorination of 2,3- and 3,4-epoxy amines by HBF4·OEt2: application to the asymmetric synthesis of (S,S)-3-deoxy-3-fluorosafingol

Treatment of a range of 2,3- and 3,4-epoxy amines with HBF(4)·OEt(2) at room temperature results in fast and efficient S(N)2-type ring-opening hydrofluorination to give stereodefined amino fluorohydrins. Operational simplicity, scalability, and short reaction time at ambient temperature are notable features of this method. The utility of this methodology is exemplified in a concise asymmetric synthesis of (S,S)-3-deoxy-3-fluorosafingol.