METAL COMPLEXED AMINO RADICALS .5. ADDITION OF COMPLEXED AMINO RADICALS TO CONJUGATED ALKENES

Dimethylamino radicals, complexed by zinc chloride, added to styrene, ±- and ²-methylstyrenes, and indene to give the corresponding bis(dimethylamino) adducts in fair to good yields. The radicals were generated by the thermal (60 °C) decomposition of the tetramethyl-2-tetrazene : zinc chloride complex. The addition of the two dimethylamino groups is shown to be a stepwise process, rather than concerted, as suggested previously by us. The relative rates of addition of the zinc chloride complexed amino radicals to substituted a-methylstyrenes were well correlated by the Hammett equation with a p value of -0.98 ± 0.04. In contrast, the p value for the addition of uncomplexed radicals was found to be 4-0.69 ± 0.03. The addition of dimethylamino radicals coordinated by ZnBr2, HgCl2, and CdCl2 to a-methylstyrene was also observed, but no addition was obtained with ZnSO4, Zn(OAc)2, Zn(C6H5)2, or Zn(C6F5)2. © 1979, American Chemical Society. All rights reserved.