Organic Phosphorus Compounds 68. The direct synthesis of tri(alkyl‐ and arylseleno)phosphites and of tris( p ‐anisyltelluro)phosphite [1]

White phosphorus reacts with organic diselenides in a dipolar aprotic solvent in the presence of a base with the formation of tri(alkyl‐ or aryl‐seleno)phosphites in good yield.\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm P}_{\rm 4} + 6{\rm RSeSeR}\mathop \to \limits^{\rm B} 4({\rm RSe})_3 {\rm P} $$\end{document}Tri(methylseleno)phosphitc shows a 31P‐chemical shift = −107 ppni ( J P, 77 Se = 233 Hz). It is readily oxidizcd in air to the corresponding selenophosphate, (CH 3 Se) 3 PO, 31 P‐chemical shift = −16 ppm. Tri(phenylseleno)phosphite reacts readily with mercury oxide to give the tri(phenylseleno)phosphate, a yellow solid of m.p. 105–110°. It also reacts with sulfur in refluxing benzene solution to give tri(phenylseleno)thiophosphate, also a yellow solid of m.p. 55–58°. However, an attempt to prepare tri(phenylseleno)selenophosphate failed. Under the same conditions as given above, white phosphorus also reacts with di‐ p ‐anisyl ditelluride to give tris( p ‐anisyltelluro)phosphite, shiny, rusty brown crystals which decompose rapidly at room temperature, but are stable for several months when kept in acetonc solution at −20°.