• Journal of Photoscience
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• v.10 no.1
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• pp.89-96
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• 2003

Two important types of $\alpha$-heterolytic fragmentation reactions of aminium radicals are discussed. In these fragmentation processes, transfer of electrofugal groups from the aminium radicals to either Lowry-Bronsted or Lewis bases produces $\alpha$-amino radicals. The results of recent studies that provided key information about the dynamics of the important aminium radical fragmentation reactions, deprotonation, desilylation, are summarized. Finally, selected examples, which demonstrate how knowledge of the relative rates of aminium radical cleavage can be used to design synthetically relevant SET-promoted photocyclization reactions, are presented.

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.604-608
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• 1997

Reactions of arenealdehyde 2-pyridylhydrazones (1) with thianthrene cation radical ($Th^{+·}$) and tris(2,4-dibromophenyl)aminium hexachloroantimonate ($Ar_3N^{+·}SbCl_6^-$) were investigated. The major product was switched depending on the cation radical being used. That is, s-triazolo[4,3-α]pyridines (2), an intramolecular cyclization product, and 1-(2-pyridyl)-1,2,4-triazoles (3), an intermolecular cycloaddition product, were obtained as a major product when reacted with $Th^{+·}$ and $Ar_3N^{+·}$, respectively in nitrile solvents. The plausible mechanisms are proposed based on both the reduction potentials of $Th^{+·}$ and $Ar_3N^{+·}$ and control experiments.

• Bulletin of the Korean Chemical Society
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• v.21 no.4
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• pp.425-428
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• 2000

Arenealdehyde 2-benzothiazolylhydrazone in thianthrene cation radicalafforded triazolo[3,4-b]benzothiazoles and 1,2,4-triazoles as major and minor product, respectively. On the contrary the similar reaction in tris(2,4-dibromophenyl)aminium hexachloroantimonate gave 1,2,4-triazoles and triazolo[3,4-b]benzothiazoles as ma-jor and minor product, respectively.