Abstract: Aqueous ammonia has been found to be a good and versatile medium for the highly selective hydrodehalogenation of polyfluoroarenes by zinc under unprecedentedly mild conditions. The reduction of pentafluorobenzoic acid, 2,3,4,5,6-pentafluorobenzyl alcohol, pentafluorobenzamide, pentafluoropyridine, heptafluoro-2-naphthoic acid, 1,3,4,5,7,8-hexafluoro-2-naphthoic acid, octafluoronaphthalene, octafluorotoluene, decafluorobiphenyl, chloropentafluorobenzene and 4-chlorotetrafluorobenzoic acid give products derived from the removal of one or two halogen atoms. A reduction mechanism, proceeding through electron capture to give a radical anion and then fragmentation of the latter, has been suggested. The observed high selectivity of the process suggests a radical anion formed by direct electron transfer from zinc to substrate. The dehalogenation regioselectivity is basically in accordance with that expected for radical anion fragmentation. (C) 1999 Elsevier Science S.A. All rights reserved.

Cite: Laev S.S. , Shteingarts V.D.
Reductive dehalogenation of polyfluoroarenes by zinc in aqueous ammonia
Journal of Fluorine Chemistry. 1999. V.96. N2. P.175-185. DOI: 10.1016/S0022-1139(99)00082-2 WOS Scopus

Dates:

Published print:

Jul 1, 1999

Identifiers:

Web of science	WOS:000081228500009
Scopus	2-s2.0-0346550082
OpenAlex	W2131104867

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