Dibenzothiophene oxidative dimerization

The electrochemical oxidation of 2,5-diaryl-1,4-dithiins (50) has been studied using various voltametric techniques and all compounds were found to undergo quasi-reversible one-electron transfers to the radical cations and dications.126 The first formal redox potential and the lifetime of the radical cation were found to decrease with increasing electron donation from the aryl ring. The major products were the 2,2 -dimers, which result via reaction of two radical cations for which rate constants are given. Dibenzothiophene radical cations reacted with tetranitromethane under... 

Oxidative coupling has been observed for benzene (52), methyl substituted benzenes (53), triphenylethylene (54), triphenyl-amines (55-59), anilines (57), carbazoles (60,61), iminobibenzyls (62), and heterocyclic phenols (71,72). Intramolecular anodic coupling reactions are used for synthesizing specific ring structures (63-68). Both dimer and octamer of dibenzothiophene have been detected (69,70)... 

In the synthetic area there have been a number of reports dealing with the photodeoxygenation of chalcogen oxides. Thus substituted dibenzothiopenes-S-oxides (62) undergo direct and sensitized photodeoxygenation at a rate which is not simply a function of the size of the substituents. The marked difference in the reactivity of the oxygenated dibenzothiophene dimers (63) and (64) was... 

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