The mechanisms of the conversion of thiophosphoryl compounds into their phosphoryl analogues by photochemically excited 3-methylpyridazine 2-oxide and by 2-methyl-3-p-nitrophenyloxaziridine; a comparison

Abstract

Reactions of tri-p-substituted triarylphosphine sulphides with 3-methylpyridazine 2-oxide, under photolysis, and with 2-methyl-3-p-nitrophenyloxaziridine both give the corresponding phosphine oxides. A detailed study and comparison of the two reactions shows that they are mechanistically quite distinct and that it is unlikely that the active oxygenating species generated by photolysis of the N-oxide, which attacks the phosphine sulphides, is an oxaziridine. The evidence presented suggests that this species may in fact be ‘oxene’.