Halodediazoniations of dry arenediazonium o-belazenedisulfonimides 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 chlor ides 3 (19 examples), bromides 4 (19 examples), and iodides 5 (9 examples) by halodediazoniation of dry arenediazonium o-benzenedisulfonimides 1 with tetraalkylammonium halides 2. The reactions were carried out in anhydrous a cetonitrile at room temperature (similar to 20 degrees C) in the presence o f copper powder and at 60 degrees C or room temperature without the catalys t. In optimal conditions the yields were from good to excellent (60 reactio ns, 61-94% yield), with only a few exceptions (8 reactions, 51-55% yield). A good amount of the o-benzenedisulfonimide (7) was always recovered from t he reactions and could then be reused to prepare salts 1. An interesting as pect of this research is the surprising role of the anion of o-benzenedisul fonimide (9) as an electron transfer agent.