N-[aryl(phenyl)phosphinoyl]hydroxylamines: influence of substituents on the competitive migration of aryl and phenyl groups in the lossen-like rearrangement of their O-methanesulphonyl derivatives

Abstract

The N-[aryl(phenyl)phosphinoyl]hydroxylamines ArPhP(O)NHOH (4)(Ar =p-XC₆H₄; X = MeO, Me, Cl, NO₂,) have been prepared from the corresponding phosphinic chlorides (3) using O-(trimethyl-silyl) hydroxylamine and converted into the O-methanesulphonyl derivatives (5). These rearrange rapidly at 0 °C with NaOMe in MeOH to give the methyl phosphonamidates ArP(O)(OMe)NHPh (6) and PhP(O)(OMe) NHAr (7). Quantitative analysis of the product mixtures gives the following values for the migration ratio p-XC₆H₄/Ph: 30 (X = MeO), 3.3 (X = Me), 0.7 (X = Cl), and 0.065 (X = NO₂).