Electron Transfer in the Decomposition of Hexaalkylhydrazine Dications

Article abstract of DOI:10.1021/jo00366a018

Rearrangements of hexaalkylhydrazine dications +N⁺R3> to α-amino ammonium cations +CHR'NR2> derived by Hofman-like degradation (loss of an α proton and NN bond cleavage to give an amino immonium cation, followed by addition of the amino group to the C=N⁺ bond) are investigated.Tricyclic dications 6²⁺ and 10²⁺ give 14⁺ and 8⁺, respectively, showing high selectivity for hydrogen loss from the methylenes in the bicyclo<2.2.2>octyl rings which can have CH bonds aligned with the NN bond over the three other types of methylene groups as well as the methyl group.Selectivity for hydrogen loss from the methyl and methylene carbons of the bicyclic cations 3²⁺ proves to be sensitive to the reaction conditions.NCH3/NCH2 attack ratios from 4 to 10 were observed for carbonate and chloride in acetonitrile (chloride in water failed to react), but a ratio of about 1 was observed for iodide in both acetonitrile and water.It is argued that iodide decomposes the dications by an electron-transfer mechanism in which the key step is hydrogen atom abstraction from the 3e-?-bonded cation radical.This is consistent with the observed even higher selectivity to HC,NN bond alignment than occurs for base attack on the dication.