eFluorination of Activated Alcohols Using Collidinium Tetrafluoroborate.

Tertiary C-F bonds are important structural designs; however, they suffer from challenging synthesis. Current methodologies use corrosive amine-HF salts or expensive and hazardous catalysts and reagents. Our group recently introduced collidinium tetrafluoroborate as an efficient fluorinating agent for anodic decarboxyfluorination reactions. Nevertheless, tertiary carboxylic acids are less readily available and more challenging to prepare than their alcohol analogues. Herein we report a practical, mild, and cheap electrochemical method to achieve deoxyfluorination of hindered carbon centers.

eHydrogenation: Hydrogen-free Electrochemical Hydrogenation.

Hydrogenation reactions are staple transformations commonly used across scientific fields to synthesise pharmaceuticals, natural products, and various functional materials. However, the vast majority of these reactions require the use of a toxic and costly catalyst leading to unpractical, hazardous and often functionally limited conditions. Herein, we report a new, general, practical, efficient, mild and high-yielding hydrogen-free electrochemical method for the reduction of alkene, alkyne, nitro and azido groups. Finally, this method has been applied to deuterium labelling.

eFluorination Using Cheap and Readily Available Tetrafluoroborate Salts.

A practical electrochemical method for the rapid, safer, and mild synthesis of tertiary hindered alkyl fluorides from carboxylic acids has been developed without the need for hydrofluoric acid salts or non-glass reactors. In this anodic fluorination, collidinium tetrafluoroborate acts as both the supporting electrolyte and fluoride donor. A wide range of functional groups has been shown to be compatible, and the possibility of scale-up using flow electrochemistry has also been demonstrated.

Electrochemical Isothiocyanation of Primary Amines.

Isothiocyanates are ubiquitous building blocks used across the fields. Nevertheless, their classical syntheses very often rely on the use of toxic and expensive reagents. Herein, we report a new practical, mild, high-yielding, and supporting-electrolyte-free electrochemical method for the preparation of aliphatic and aromatic isothiocyanates from amine and carbon disulfide.

Electrosynthesis of Stabilized Diazo Compounds from Hydrazones.

An electrochemical synthesis of diazo compounds from hydrazones in yields as high as 99% was performed. This method was elaborated as a useful synthetic method and demonstrated on various diazo compounds (24 examples). Apart from exhibiting an efficiency that matched that of commonly used harsh and toxic chemical oxidants, this reaction is practically simple to set up, requires mild conditions, and is highly electron efficient (3 F/mol).