O-Sulphonyl-N-phosphoylhydroxylamines: nucleophilic attack at nitrogen by dimethyl sulphide and allyl methyl sulphide leading to N-phosphoyl sulphilimines

Abstract

The O-sulphonyl-N-phosphoylhydroxylamines RR′P(O)NHX [R,R′= Ph or p-MeC₆H₄O; X = OMs or ONs] generally react with dimethyl sulphide and allyl methyl sulphide at room temperature in the absence of base. Nucleophilic attack at nitrogen, with displacement of the sulphonate anion, gives the protonated N-phosphoyl sulphilimine [e.g.(6)] which is converted into the free sulphilimine [e.g.(7)] on treatment with base. The allylic sulphilimines [e.g.(9)] are labile, undergoing [2,3]-sigmatropic rearrangement to N-phosphoyl-N-allylsulphenamides [e.g.(10)]. In the light of these results, the formation of some sulphilimine when the base-induced rearrangement of Ph₂P(O)NHOMs is carried out in dimethyl sulphide need not be seen as evidence for a nitrene mechanism.