REACTION OF ORGANO-THALLIUM(III) AND -MERCURY(II) COMPOUNDS WITH NITRONATE ION AND N-BENZYL-1,4-DIHYDRONICOTINAMIDE:REDUCTIVE ELECTRON-TRANSFER ACTIVATION OF THE METAL-CARBON BOND TOWARD HOMOLYSIS

Article abstract of DOI:10.1016/0022-328X(83)85041-4

Some organothallium(III) diacetates, RTl(OAc)2 reacted with the anion of 2-nitropropane, affording moderate to good yields of the coupling products, RMe2CNO2.Mechanistic studies suggested that this reaction involved the alkylthallium(III) analog, proceeding primarily through the radical non-chain substitution mechanism, in contrast to the radical chain substitution mechanism in the corresponding reaction of alkylmercury(II) compounds.Aryl radical intermediates also participated in the reaction to some extent, while the reaction of the styrylthallium(III) analog was proposed to proceed through the non-radical, vinylic nucleophilic substitution mechanism.A similar mechanistic contrast between the reactions of the alkyl-thallium(III) and -mercury(II) compounds was also observed in the clean hydrodemetallation of these organometallics with N-benzyl-1,4-dihydronicotinamide.The key to these radical reactions of the organo-thallium(III) and-mercury(II) compounds was suggested to be reductive electron-transfer activation of the M-C bond toward homolysis, the ease of this process decreasing in the order Tl-C > Hg-C.