A diastereomeric mixture of secondary phosphine oxide is stereospecifically converted to chlorophosphine salt by treatment with oxalyl chloride, which stereoselectively affords P-inverted or retained tertiary phosphines, depending on the substitution with aliphatic or aromatic Grignard reagents, respectively, in high to 99% yield and 99:1 dr. The repulsion of π-electron on aryl to lone electron pair on phosphorus is proposed for the P-retained substitution.

The preparation, application, and reaction mechanism of sodium phosphide R2PNa and other alkali metal phosphides R2PM (M = Li and K) have been studied. R2PNa could be prepared, accurately and selectively, via the reactions of SD (sodium finely dispersed in mineral oil) with phosphinites R2POR′ and chlorophosphines R2PCl. R2PNa could also be prepared from triarylphosphines and diarylphosphines via the selective cleavage of C–P bonds. Na was superior to Li and K for these reactions. R2PNa reacted with a variety of ArCl to efficiently produce R2PAr. ArCl is superior to ArBr and ArI since they only gave low yields of the products. In addition, Ph2PNa is superior to Ph2PLi and Ph2PK since Ph2PLi did not produce the coupling product with PhCl, while Ph2PK only gave a low yield of the product. An electron-withdrawing group on the benzene ring of ArCl greatly accelerated the reactions with R2PNa, while an alkyl group reduced the reactivity. Vinyl chloride and alkyl chlorides RCl also reacted efficiently. While t-BuCl did not produce the corresponding product, admantyl halides could give the corresponding phosphine in high yields. A wide range of phosphines were prepared by this method from the corresponding chlorides. Unsymmetric phosphines could also be conveniently generated in one pot starting from Ph3P. Chiral phosphines were also obtained in good yields from the reactions of menthyl chlorides with R2PNa. Possible mechanistic pathways were given for the reductive cleavage of R3P by sodium generating R2PNa and the substitution reactions of R2PNa with ArCl generating R2PAr.

For over half a century, thousands of tons of triphenylphosphine oxide Ph3P(O) have been produced every year from the chemical industries as a useless chemical waste. Here we disclose efficient transformations of Ph3P(O) with cheap resource-abundant metallic sodium finely dispersed in paraffin oil. Ph3P(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 Ph3P(O) to be used as a precious starting material for highly valuable phosphorus compounds.