Alkaline metal fluorides in graphite - new catalysts in organic synthesis. I. Reactions of polyfluoroaromatic compounds with O- and N-nucleophilic agents
The paper reports the use of new catalysts - alkaline metal fluorides in graphite of the general formula C8MF, where M=Li, Na, K, Rb or Cs, in the reactions of polyfluoroaromatic compounds with aromatic OH-acids and piperidine. These compounds are shown to have a high activity in the above processes, exceeding that of similar free fluorides of alkaline metals.
作者:V. M. Vlasov、V. V. Aksenov、P. P. Rodionov、I. V. Beregovaya、L. N. Shchegoleva
DOI:10.1023/a:1015371212613
日期:——
The kinetics of the reactions of pentafluoropyridine with potassium aroxides, leading to formation of polyfluorinated aryl pyridyl ethers, conform to the Bronsted equation. The data obtained for potassium pentafluorophenoxide deviate from the general correlation because of readily occuring reverse reaction, replacement of the pentafluorophenoxy group by released fluoride ion. PM3 calculations of the electronic structure of the reagents, intermediate sigma-complexes, and products showed that the replacement of fluorine in pentafluoropyridine is a charge-controlled process, whereas unusually easy replacement of the pentafluorophenoxy group in the corresponding aryl pyridyl ether by fluorine is explained by structural features of its lowest unoccupied molecular orbital.