Arylations using diazonium tetrafluoroborate and pyridine

Decomposition of Aryldiazonium Ions in Homogenous Solutions Part II: Arylations with benzenediazonium ions and p‐nitrobenzenediazonium ions in dimethyl sulfoxide

“…In fact, we obtained at 50" less, and at 80" the same percentage of m-substitution. Similar ratios of less and more m-product exist when our data are compared with those of Abramovitch & Saha [13] for the phenylation of nitrobenzene at 75" with phenyl radicals formed in a solution of benzenediazonium salt in pyridine. On the other hand, Kobayashi et al [GI found only 5.4% m-product in the phenylation of nitrobenzene in DMSO at lo", generating the phenyl radicals with nitrite ions.…”

“…Alternative (b) may operate in DMSO by analogy with the homolytic decomposition induced by pyridine [13] [20]: DMSO has electron donating properties comparable with pyridine, as seen from the equilibrium constants for complex formation with iodine molecules ( Table 3). At least for the solution of p-nitrobenzenediazonium ions in DMSO the electronic spectra clearly prove the stability of the charge transfer complexes with DMSO [24].…”

Three‐Component Metal‐Free Arylation of Isocyanides

“…When para ‐nitrophenyldiazonium tetrafluoroborate was added to a solution of cyclohexyl isocyanide in a water/acetonitrile mixture, we observed a slow reaction leading to the expected amide in 10 % yield after one hour (Scheme ). Diazonium salts are known to generate aryl radicals more efficiently in the presence of nucleophilic weak bases such as tertiary amines,8 pyridine,9 or sodium acetate 10. In addition, the reaction should progress with evolution of tetrafluoroboric acid, a sufficiently strong acid to trigger the hydrolysis of the acid sensitive isocyanide.…”

Arylation of Pyridine with 9,10-Dioxoanthracenyl-1(2)-diazonium Hydrosulfates

“…Here we report on the results of the reaction of 9,10-dioxoanthracenyl-1(2)-diazonium hydrosulfates 1 and 2 (Scheme 1) prepared by the method [15] with pyridine under the modified Gomberg-Bachmann reaction conditions [16,17] at 45-70°C (method a) and in the presence of catalytic amounts of CuCl 2 at 0-20°C (method b). It was found that in both cases, irrespective of the location of the diazonium function, the pyridine arylation reaction afforded a mixture of isomeric 2-pyridyl-, 4-pyridyl-, and 3-pyridylanthraquinones 3-5 and 6-8 in the approximate ratio of 4 : 2 : 1 (LC-MS).…”