Balz–Schiemann reaction

Balz-Schiemann reaction
Named after Günther Balz
Günther Schiemann
Reaction type Substitution reaction
Identifiers
Organic Chemistry Portal balz-schiemann-reaction
RSC ontology ID RXNO:0000127

The Schiemann reaction (also called the Balz–Schiemann reaction) is a chemical reaction in which a primary aromatic amine is transformed to an aryl fluoride via a diazonium tetrafluorofluoroborate intermediate.[1][2] Both thermal and photolytic decomposition of the diazonium intermediate proceed through an arene cation, as evidenced by the equal product ratios in both cases.[3] Named after the German chemists Günther Schiemann and Günther Balz, this reaction is the preferred route to fluorobenzene and some related derivatives,[4] including 4-fluorobenzoic acid.[5]


The reaction is similar to the Sandmeyer reaction, which converts diazonium salts to other aryl halides.[6] Other Counterions have been used in place of tetrafluoroborates, such as hexafluorophosphates (PF6-) and hexafluoroantimonates (SbF6-) with improved yields for some substrates.[7]Large-scale thermal decomposition of the diazonium salts is potentially explosive.

References

  1. ↑ Günther Balz; Günther Schiemann (1927). "Über aromatische Fluorverbindungen, I.: Ein neues Verfahren zu ihrer Darstellung". Ber. 5 (60): 1186–1190. doi:10.1002/cber.19270600539.
  2. ↑ Roe, A. Org. React. 1949, 5, 193. (Review)
  3. ↑ Becker, H. G. O., Isreal, G. J. Prakt. Chem. 1978, 321, 579-586.
  4. ↑ Flood, D. T. (1943). "Fluorobenzene". Organic Syntheses. ; Collective Volume, 2, p. 295
  5. ↑ G. Schiemann; W. Winkelmüller (1943). "p-Fluorobenzoic Acid". Organic Syntheses. ; Collective Volume, 2, p. 299
  6. ↑ Swain, C. G.; Rogers, R. J. (1975). "Mechanism of formation of aryl fluorides from arenediazonium fluoborates". J. Am. Chem. Soc. 97 (4): 799–800. doi:10.1021/ja00837a019.
  7. ↑ Furuya, Takeru; Klein, Johannas E. M. N.; Ritter, Tobias (2010). "Carbon-Fluorine Bond Formation for the Synthesis of Aryl Fluorides". Synthesis. 11: 1804–1821 – via Reaxys.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.