Halodediazoniations of dry arendiazonium o-benzenedisulfonimides in the presence or absence of an electron transfer catalyst. Easy general procedures to prepare Aryl chlorides,bromides,and iodides

The paper reports the results of a wide study aimed at preparing aryl chlorides (19 examples), bromides (19 examples), and iodides (9 examples) by halodediazoniation of dry arenediazonium o-benzenedisulfonimides with tetraalkylammonium halides. The reactions were carried out in anhydrous acetonitrile at room temperature (~20 C) in the presence of copper powder and at 60 C or room temperature without the catalyst. In optimal conditions the yields were from good to excellent (60 reactions, 61-94% yield), with only a few exceptions (8 reactions, 51-55% yield). A good amount of the o-benzenedisulfonimide was always recovered from the reactions and could then be reused to prepare arenediazonium salts. An interesting aspect of this research is the surprising role of the anion of o-benzenedisulfonimide as an electron transfer agent.