Unusual solvent-dependent behaviour of hydroxyiminophosphonamidates in the Beckmann reactions: choice between rearrangement or fragmentation to metaphosphonamidate species

Abstract

Methyl α-hydroxyiminobenzyl-N-tert-butylphosphonamidate undergoes Beckmann rearrangement (BR) when heated in toluene, but fragmentation (via metaphosphonamidate) to a phosphoramidate and PhCN when heated in BuOH, supporting the assumption of a common intermediate for the BR and the Beckmann fragmentation; polar solvents retard the rearrangement.