Electrochemical reduction of polyhalogenated aryl derivatives in the presence of pinacolborane: Electrosynthesis of functionalised arylboronic esters

The electroreduction of several dihalogenated aryl compounds was carried out in the presence of pinacolborane as the electrophile for the synthesis of halogenated arylboronic ester derivatives. The nature and the relative position of the halogen substituents strongly influence the boration results. The electroreduction of a trihalogenated derivative was also examined. Reactions were carried out in THF in a single-compartment cell in the presence of a Mg anode.