Addition of aryl radicals generated from electrochemical reduction of aryl halides on carbon-carbon double bonds.

✍ Scribed by Zoubida Chami; Monique Gareil; Jean Pinson; Jean-Michel Saveant; André Thiebault

• Publisher: Elsevier Science
• Year: 1988
• Tongue: French
• Weight: 218 KB
• Volume: 29
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)80170-7

✦ Synopsis

Aryl radicals generated by electrochemical reduction of aryl halides in aprotic medium react with styrene and its derivatives to give arylated addition compounds. The electrochemical reduction of aryl halides offers a convevient means to generate aryl radicals in a controlled manner through the cleavage of the initially formed anion radical ArX + e-1 ArX'-(0) kl ArX'-+ Ar'+ X-(1) This possibility has been extensively used in the electrochemical catalysis of SRNl aromatic nucleophilic substitutionl,z. We now show that aryl radicals generated in the same way from aryl halides can be reacted with carboncarbon double bonds yielding the corresponding hydroarylated compounds3. Starting, for example, from 4chlorobenzonitrile, in liquid NJ-la, we can generate the Ccyanophenyl radical at the first reduction wave4 according to reactions (0) and (1) and make it react with an olefin : R Ar' + >=< k2, Ar-tl-R However, since reaction (1) is very fast (kt = 9.3 108 s-l)te the cyanophenyl radical will be formed close to the electrode surface and be rapidly reduced there : Ar' + e-+ A7 (+H+ +ArH) (3)