Abstract: Sodium allylvinylphosphinate (1) rearranges thermally to sodium hydrogen pent-4- enephosphonate (3) in virtually quantitative yield. The reaction probably constitutes a phospho-Cope rearrangement and presumably proceeds by way of the monomeric metaphosphonate 2 as a reactive intermediate. The half-time for the reaction is 4.67 h in water at 193.6 f 1.0" C and 6.03 h in ethanol. By contrast, ethyl allylvinylphosphinate ...
