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 anilines (1) are transformed to aryl fluorides (3) via diazonium fluoroborates (2).^[1][2] Named after the German chemists Günther Schiemann and Günther Balz, this reaction is the preferred route to fluorobenzene and some related derivatives,^[3] including 4-fluorobenzoic acid.^[4]

${\displaystyle {\ce {{\overset {aniline}{\underset {\mathbf {1} }{Ar-NH2}}}+HBF4->[{\ce {HNO2}}]{\overset {diazonium\ fluoroborates}{\underset {\mathbf {2} }{Ar-{\underset {+}{N}}{\equiv }N}}}+BF4^{-}->[\Delta ]{\overset {aryl\ fluoride}{\underset {\mathbf {3} }{Ar-F}}}+{BF3}+N2}}}$

The reaction is similar to the Sandmeyer reaction, which converts diazonium salts to other aryl halides.^[5]

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. Flood, D. T. (1943). "Fluorobenzene". Org. Synth.; Coll. Vol., 2, p. 295
4. G. Schiemann; W. Winkelmüller (1943). "p-Fluorobenzoic Acid". Org. Synth.; Coll. Vol., 2, p. 299
5. Swain, C. G.; Rogers, R. J. (1975). "Mechanism of formation of aryl fluorides from arenediazonium fluoborates". J. Am. Chem. Soc. 97: 799–800. doi:10.1021/ja00837a019.