Organophosphorus intermediates. Part VI. Base-catalysed reaction of methyl phosphinate with tetraphenylcyclopentadienone

Abstract

Tetraphenylcyclopentadienone is rapidly reduced by methyl phosphinate in the presence of base, the major products being 2,3,4,5-tetraphenylcyclopent-3-enone (3) and dimethyl phosphonate, formed together with small amounts of trans- and cis-2,3,4,5-tetraphenylcyclopent-2-enone and 4- and 5-hydroxy-2,3,4,5-tetraphenylcyclopent-2-enones, (5) and (6). A mechanism involving decomposition of the monoanion of methyl phosphinate to hydride ion and methyl phosphenite is suggested to account for the products formed. No compounds with carbon–phosphorus bonds were detected.