N-(Dialkylphosphinoyl)hydroxylamines : Preparation using N,O-Bis(trimethylsilyl)hydroxylamine and Migration of Simple Alkyl Groups in the Rearrangements of their O-p-Nitrobenzenesulphonates

Article abstract of DOI:10.1016/S0040-4020(01)90367-9

Treatment of Prⁱ2P(O)Cl with Me3SiNHOSiMe3 gives Prⁱ2P(O)NHOSiMe3, which is desilylated by methanol giving Prⁱ2P(O)NHOH.The O-p-nitrobenzenesulphonyl derivative of this rearranges with KOBu^t in Bu^tOH, an isopropyl group migrating from P to N and the phosphonamidate PrⁱP(O)(OBu^t)NHPrⁱ being formed quantitatively.Rearrangement also occurs in other alcohols (MeOH, EtOH, PrⁱOH), but not quite as cleanly.In Bu^tNH2 the phosphinoylhydrazine Prⁱ2P(O)NHNHBu^t is formed as well as the rearrangement product, PrⁱP(O)(NHBu^t)NHPrⁱ.The p-nitrobenzenesulphonyl derivatives of Et2P(O)NHOH and PrⁱMeP(O)NHOH, prepared similarly with Me3SiNHOSiMe3, also rearrange quantitatively with Bu^tOH - KOBu^t.In the latter case, the migratory aptitudes of the two alkyl groups (Prⁱ and Me) are almost identical.