Various substituted carboxylic acid 2-chloro-and 2-bromoanilides 1a–j react with triethylphosphite in the presence of anhydrous NiCl2 or NiBr2 to give o-acylamido- benzenephosphonic acid esters 2a–g and 2j. Yields depend strongly on the substituents. 2- Fluoro-4, 6-dibromoacetanilide 1g reacts only at 6-position, indicating an o-directed process. Based on substituent effects, we infer a mechanism via Ni (0) intermediates that insert into ...
