Transhalogenation

Transhalogenation (also: halide metathesis) is a substitution reaction in which a halogen atom of a halogen compound is exchanged for another halogen atom, for example the reaction of an alkyl chloride to an alkyl fluoride by means of sodium fluoride:

R-Cl + NaF → R-F + NaCl

If the halogen compound is an organic compound, this is called Finkelstein reaction.[1] However, it is also possible, for example, to produce phosphorus fluoride compounds by transhalogenating chlorine, bromine or iodine bound to phosphorus with a metal fluoride.[2]

Details and biological use
An enzyme-catalyzed transhalogenation.

As a halogen source for transhalogenation, metal halides (such as sodium fluoride or lithium fluoride) are often used, but also the use of onium halides is possible.[1] Transhalogenation has been described as a gentle method for the synthesis of fluoroorganylboranes.[3] It is also possible to produce aryliodides from the corresponding aryl chlorides or aryl bromides.[4]

One investigation showed a possibility to perform transhalogenation by means of genetically modified enzymes (haloalkanes dehalogenases, HLDs).[5]

Literature
  • Yoel Sasson (2009-12-15). "Formation of Carbon-Halogen Bonds (Cl, Br, I)". PATai's Chemistry of Functional Groups. PATai's Chemistry of Functional Groups. Chichester, UK: John Wiley & Sons, Ltd. pp. pat0011. doi:10.1002/9780470682531.pat0011. ISBN 978-0-470-68253-1.
  • "transhalogenation - Wiktionary".
gollark: Maybe libdatatape would be useful if I swap out the random proprietary (and mostly made by someone else and tweaked by me because it did integers wrong) serialization format for CBOR, or let you provide your own.
gollark: I think a big one is RXI's JSON thing, although that got obsoleted on newer versions by `textutils.unserialiseJSON` or whatever it is.
gollark: The particularly good ones are generally from other people.
gollark: Well, I have some libraries, I don't think they're mostly all that *useful*.
gollark: `a_function("string with spaces")` or even `a_function "string with spaces"` which is neat.

References
  1. Yoel Sasson (2009-12-15). "Formation of Carbon-Halogen Bonds (Cl, Br, I)". PATai's Chemistry of Functional Groups. PATai's Chemistry of Functional Groups. Chichester, UK: John Wiley & Sons, Ltd. pp. pat0011. doi:10.1002/9780470682531.pat0011. ISBN 978-0-470-68253-1.
  2. DE 68918542T, "Verfahren zur Transhalogenierung einer Halogenphosphor-Verbindung mit Fluorwasserstoff", published 1989-08-30
  3. Gerd Bir, Wolfgang Schacht, Dieter Kaufmann (1988-02-23), "Eine allgemeine, einfache und schonende Synthesemethode für Fluororganylborane", Journal of Organometallic Chemistry (in German), 340 (3), pp. 267–271, doi:10.1016/0022-328X(88)80020-2, ISSN 0022-328XCS1 maint: multiple names: authors list (link)
  4. Alex C. Bissember, Martin G. Banwell (2009-07-03), "Microwave-Assisted Trans-Halogenation Reactions of Various Chloro-, Bromo-, Trifluoromethanesulfonyloxy- and Nonafluorobutanesulfonyloxy-Substituted Quinolines, Isoquinolines, and Pyridines Leading to the Corresponding Iodinated Heterocycles†", The Journal of Organic Chemistry, 74 (13), pp. 4893–4895, doi:10.1021/jo9008386, ISSN 0022-3263, PMID 19480440
  5. Andy Beier, Jiri Damborsky, Zbynek Prokop (2019-04-17), "Transhalogenation Catalysed by Haloalkane Dehalogenases Engineered to Stop Natural Pathway at Intermediate", Advanced Synthesis & Catalysis, pp. adsc.201900132, doi:10.1002/adsc.201900132, ISSN 1615-4150CS1 maint: multiple names: authors list (link)
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