Reaction between aldehyde oximes and methanesulphinyl chloride

Abstract

The reactions of several (E)- and (Z)-benzaldehyde oximes with methanesulphinyl chloride at –70 °C give benzaldehyde O-methylsulphinyloxime intermediates. These rearrange above 0 °C to give the corresponding sulphonylimines in good yield, accompanied by minor products including nitriles and products derived from the decomposition of methanesulphinic acid. N.m.r. spectra (¹H and ¹³C) show strong polarizations in the sulphonylimines, indicating a radical-cage mechanism. Further evidence for the involvement of radicals comes from the observation of strong e.s.r. signals. Kinetic measurements of the activation parameters support the conclusions that homolytic dissociation of the N–O bond is the major pathway in this rearrangement.