S(N)2 REACTION VERSUS ELECTRON-TRANSFER IN THE OXYGEN-TRANSFER BY DIMETHYLDIOXIRANE TO NITROGEN HETEROARENES

The rates of the N oxidation of aromatic amines with dimethyldioxirane (DMD) have been compared with those of the methylation of the same compounds with methyl iodide, and an excellent correlation (r = 0.977) for the log k values was obtained. The correlation with the ionization potentials was significantly worse. Thus, the N oxidation with DMD proceeds through an S(N)2 rather than an electron transfer (ET) mechanism [Eq. (a)]. [GRAPHICS]