The Stereochemical Course of Migration from Phosphorus to Nitrogen in the Photo-Curtius Rearrangement of Phosphinic Azides (Harger Reaction)

Article abstract of DOI:10.1021/jo00262a002

The homochiral phosphinic azides (R,R)-1 and (S,S)-1 have been prepared in enantiomerically pure form by resolution of diastereomeric phosphinamides derived from (S)-1-phenylethylamine and (R)-phenylglycine.Irradiation of the azides in methanol induced a photo-Curtius rearrangement of phosphonamidates in which the stereogenic carbon unit migrated to a nitrogen atom.Hydrolysis of the phosphonamidates produced 1-phenylethylamine, which was 99.0percent ee and of the same configuration as the carbon unit in the starting azide (99.0percent net retention).The implication for asymmetric synthetic methodology is discussed.