Supporting Electrolyte and π-Conjugation Effects in Bromoanthracene-Mediated Electrocatalytic C–N Coupling of <i>N</i>-Tosyl Aminobiphenyl

Redox induced halogen bonding donor mediators enable indirect electrosynthesis via electrochemically enhanced σ-hole electrophilicity. Here we further investigate the sulfonamide substrate N-Ts-aminobiphenyl, which previously showed low conversion, using 9-bromo-10-arylanthracene mediators for intramolecular C–N coupling. With 9-bromo-10-(p-cyanophenyl)anthracene, yields increased with the donor number of the supporting electrolyte anion up to an optimum, whereas strongly donating anions suppressed catalysis. Bulky 10-aryl groups improved yields by kinetically protecting the spin-dense C10 site and limiting π-conjugation in the radical cation to maintain bromine σ-hole electrophilicity. Control experiments confirm the essential role of Br.