Iodophenylsulfonates and Iodobenzoates as Redox-Active Supporting Electrolytes for Electrosynthesis

Hypervalent iodine compounds constitute a popular class of reagents in organic chemistry. Regardless of whether they are generated in situ from an iodoarene precursor with a terminal oxidant or used in stoichiometric amounts, the resulting separation and waste issues are major challenges en route to sustainable and scalable processes. The electrochemical generation of iodine(III) compounds represents an attractive alternative, since electric current is used as traceless oxidant and unstable or hazardous species are conveniently generated in situ. In this context, we have explored the possibility for the use of iodoarene sulfonates and iodobenzoates as ex-cell mediators for electrosynthesis in 1,1,1,3,3,3-hexafluoroisopropanol. While 2-, 3- and 4-iodobenzoate salts proved to be impractical for various reasons, 2- and 4-iodobenzenesulfonates salts can be selectively oxidized to the iodine(III) species and used for synthetic applications. The ionic tag on the mediator allows for electrolysis without supporting electrolyte additives and enables a straightforward recovery from the product mixture.