Preparation and characterisation of N-(diphenylphosphinoyl)hydroxylamine, and conversion into O-sulphonyl derivatives that undergo Lossen-like rearrangement

Abstract

Having previously shown that diphenylphosphinic chloride (1a) forms O-(diphenylphosphinoyl)hydroxylamine (3a) with hydroxylamine, we have now established that N-(diphenylphosphinoyl)hydroxylamine (2a) can be obtained in good yield by reaction of (1a) with O-trimethylsilylhydroxylamine followed by methanolytic removal of the silyl blocking group. The di-p-tolyl (2b) and bis-p-methoxyphenyl (2c) analogues can be prepared in a similar way. N-(Diphenylphosphinoyl)hydroxylamine is acetylated at the O atom with acetic anhydride, and is sulphonylated at O with methanesulphonyl chloride and toluene-p-sulphonyl chloride. The N-(diphenylphosphinoyl)-O-sulphonylhydroxylamines (8) and (12a) undergo rapid and quantitative Lossen-like rearrangement with methanol–sodium methoxide to give methyl N,P-diphenylphosphonamidate (11). Comparable rearrangements are observed with t-butylamine, aniline–triethylamine, and phenol–triethylamine.