Stereochemistry of organophosphorus compounds - Communication 8. Configuration and conformational mobility of trans-2,3-diphenyl-4-dimethoxyphosphonoisoxazolidine ring

1. The 1,3-bipolar cycloaddition of dimethyl vinylphosphonate to C,N-diphenylnitrone gave trans-2,3-diphenyl-4-dimethoxyphosphonoisoxazolidine, the structure and configurations of which were proved via the1H and31P NMR,1H -{31P} NMDR, and IR spectra. 2. From the stereospecificity of the vicinal spin-spin coupling constants3JPCCH and3JHCCH and the temperature dependence of the NMR spectra it follows that the isoxazolidine ring is found in the pseudorotation state. © 1975 Plenum Publishing Corporation