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The acylation of aromatic compounds with aroyl triflates can be performed in organic solvents (1,2-dichloroethane) without Friedel−Crafts catalysts. These reaction conditions allow kinetic investigations of the reaction in homogeneous solution. From rate measurements evidence is given that in all cases the aroyl triflates 1, 6, and 11 dissociate primarily into the corresponding acylium ions which subsequently react with the aromatic compounds. The rate-determining step, either the dissociation of the aroyl triflates or the reaction of the acylium ions with the aromatic, can be assigned definitely from the experimental data. From the kinetic measurements in the presence of an excess of base unequivocal evidence of acylium ions as the reacting electrophiles in all cases investigated is given.

Dimeric u-complexes 2, postulated intermediates in the oxidative dimerization of aromatics, were obtained by oxidation of tripprolidin-1-ylbenzenes la-f with silver nitrate. Treatment of 2 with strong base gave biphenyls 4. In solution, especially under the influence of light, compounds 2 dissociate to radical cations lo+, which react irreversibly with solvent under H abstraction to give u-complexes 3. Crystal structures were determined by X-ray diffraction methods for compounds 2a and 2c. Reactions of triaminobenzenes 8 and 9 with bromine and halocyanogens gave mixtures of substitution (lo/ 11) and dimerization products (12/ 13). This product formation can be plausibly explained in terms of known steric and electronic factors of both reaction partners.

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