THE DIRECT PREPARATION OF THE ESTERS OF P-NITROBENZYLPHOSPHONIC ACID FROM P-NITROBENZYL HALIDES

The reaction of sodium diisopropyl phosphite with p-nitrobenzyl bromid e tvas studied in detail by (1) isolation and identification of all pr oducts and (2) studying the effects of radical traps, such as dicycloh exylphosphine, di-tert-butylnitroxide, and the diisopropyl phosphite a nion, on product distribution. The results of the experiments carried out are compatible with a proposed X-philic substitution/SET tandem me chanism. It was demonstrated that p-nitrobenzyl chloride is also a goo d single-electron acceptor from the p-nitrobenzyl anion. The anion rad ical derived from p-nitrobenzyl chloride decomposes into the p-nitrobe nzyl radical which couples with an appropriate anion if it is present in a high enough concentration in the reaction mixture, to produce the dimer or the p-nitrobenzylphosphonate. (C) 1996 John Wiley & Sons, In c.