Synthesis and study of the thermal stability of siliconcontaining esters of phosphorus acids. 4. Thermal rearrangement of trimethylsilylmethyl esters of phosphorus acids

Abstract

NMR spectroscopy has been used to study the thermal rearrangement of siliconeopentyl esters of phosphorus acids Me3SiCH2OP(O)R2 (I, R=CF3CH2O, PhO, t-BuCH2O, Bu). It has been established that in all cases the products of the rearrangement are the respective silyl esters Me2EtSiOP(O)R2 (II). The thermal rearrangement of (Me3SiCH2O)2P(O)OR′ (III, R'=Ph, t-BuCH2, Me3SiCH2) is similar. It has been shown that electronic and steric attributes of the substituents R and R′ on the phosphorus atom are practically without effect on the extent of the thermal rearrangement. The presence of acidic additives, and initiators and inhibitors of radical reactions did not significantly influence the course of the rearrangement. It was concluded that this rearrangement apparently takes place as a result of heterolysis of the C-OP bond and simultaneous nucleophilic attack on the silicon atom by the phosphoryl part of the molecule.