Scope and Limitations of the Aromatic Anionic [1,3] P–O to P–C Rearrangement in the Synthesis of Chiral o-Hydroxyaryl Diazaphosphonamides

The influence of numerous parameters in the aromatic anionic [1,3] P–O to P–C rearrangement in the synthesis of chiral o-hydroxyaryl diazaphosphonamides has been envisaged. Various strong bases such as LDA, sec-BuLi, tert-BuLi have been conveniently used. The scope of the regioselectivity of the rearrangement has been particularly studied varying the nature of the phenoxy group implied in this reaction. A totally diastereoselective P–O to P–C migration rearrangement has been observed starting from a thiophosphonamide precursor. Moreover, starting from a phenylthio substituted phosphonamide, a totally diastereoselective P–S to P–C rearrangement of the diazaphosphonamide moiety has also been demonstrated.