Conversion of triphenylphosphine oxide to organophosphorus via selective cleavage of C-P, O-P, and C-H bonds with sodium.

For over half a century, thousands of tons of triphenylphosphine oxide Ph ₃ P(O) have been produced every year from the chemical industries as a useless chemical waste. Here we disclose efficient transformations of Ph ₃ P(O) with cheap resource-abundant metallic sodium finely dispersed in paraffin oil. Ph ₃ P(O) can be easily and selectively transformed to three reactive organophosphorus intermediates-sodium diphenylphosphinite, sodium 5H-benzo[b]phosphindol-5-olate and sodium benzo[b]phosphindol-5-ide-that efficiently give the corresponding functional organophosphorus compounds in good yields. These functional organophosphorus compounds are difficult to prepare but highly industrially useful compounds. This may allow Ph ₃ P(O) to be used as a precious starting material for highly valuable phosphorus compounds.
(© 2020. The Author(s).)