Synthesis, Configuration, and Chemical Shift Correlations of Chiral 1,3,2-Oxazaphospholidin-2-ones Derived from l-Serine

Article abstract of DOI:10.1021/jo00288a023

The reaction between (S)-methyl N-benzylserinoate and phosphorous oxychloride leads to the diastereomeric chloro-1,3,2-oxazaphospholidin-2-ones.Reaction of the chloridates with alcohols or phenols in the presence of base affords the corresponding alkoxy (or aryloxy) derivatives (66-94percent), which were readily separated by standard chromatographic methods.The stereochemical arrangement of these compounds was established by NMR chemical shift correlations (carbon-13 and phosphorus-31) and single-crystal X-ray analysis.The trans geometry of the carbomethoxy and exocyclicphosphorus ligand resulted in approximately a 1 ppm upfield shift in the phosphorus-31 spectra relative to the cis isomer.The carbon-13 NMR spectra revealed an opposite trend to the heteroatom-bound alkyl region with most of the trans isomer signals appearing downfield (0.2-1.2 ppm) from the corresponding cis isomer.