Reaction of three-coordinate phosphorus compounds with organophosphorus pseudohalogens. Part 4. The mechanism of interaction between bis(phosphinoyl) diselenides [R1R2P(O)Se]2 with three-coordinate phosphorus compounds

Abstract

The reaction of bis(phosphinoyl) diselenides R¹R²P(O)Se–SeP(O)R¹R²1 with P(III) compounds has been investigated and its mechanistic features have been elucidated by variable temperature ³¹P NMR spectroscopy. These studies show that in most cases phosphonium intermediates 7, 13 and 10, 16 are involved. In the case when ligands on P(III) increase the stability of the five-coordinate structure, a phosphorane intermediate is observed. In the isomerization 7→10 and 13→16 the pathway of decomposition (deselenization, deoxygenation or dealkylation) to give stable end products is influenced by electronic and steric factors.