THE MECHANISM OF NUCLEOPHILIC SUBSTITUTION IN HALOPYRYLIUM AND HALOBENZOPYRYLIUM SALTS

Abstract

The electrochemical behavior of 4-chloro-2,6-diphenylpyrylium and 4-chloro(bromo)flavylium perchlorates has been studied. Their reaction with nucleophiles has also been studied. It was shown that nucleophilic substitution in these compounds occurs through a stage of forming a charge-transfer complex which passes into an ion-radical pair as a result of a one-electron transfer. Heterolytic fission of the C–Hal bond occurs at the stage of the radical or adduct of the substituted pyrylium (flavylium) salt and nucleophile.

Authors: A. I. Fomenko, V. N. Storozhenko, S. G. Storozhenko, A. O. Manyashin, N. T. Berberova, and O. Yu. Okhlobystinю

English Translation in Chemistry of Heterocyclic Compounds, 1999, 35 (6), pp 653-657

http://link.springer.com/article/10.1007/BF02251620