The one-pot procedure with prolonged oxidation time is generally only efficient if the coupling partner 4 is a relatively reactive boronic acid. The synthesis of diaryliodonium salts with two electron-deficient aryl groups proved feasible through a stepwise reaction with oxidation of the iodoarene to (diacetoxyiodo)arenes 8, which were isolated and reacted with arylboronic acids 4 (Scheme 4b). Notably, no reaction was observed in attempted couplings of electron-poor boronic acids 4 with the corresponding Koser's reagents 7, despite literature reports on organoboron reagents being coupled with both Koser's derivates 7 and (diacetoxyiodo)arenes 8. Scheme 4. Synthesis of electron-deficient 3-BF4 and 3-OTf.