Fries rearrangement



The Fries rearrangement, named for the German chemist Karl Theophil Fries, is a lewis acids.[1][2][3]

Mechanism

Despite many efforts a definitive carbocation intermediate.

In the first reaction step a ortho product prevails.

Scope

catalysts altogether research into alternative heterogeneous catalysts is actively pursued.

Limits

In all instances only Friedel-Crafts acylation.

Photo-Fries rearrangement

In addition to the ordinary thermal phenyl ester reaction a so-called substituents on the aromatic group. Because the yields are low this procedure is confined to the laboratory.

Anionic Fries rearrangment

In addition to Lewis acid and photo-catalysed Fries rearrangements, there also exists an anionic Fries rearrangement. In this reaction, the aryl ester undergoes ortho-metallation with a strong base, which then rearranges in a nucleophillic attack mechanism.

References

  1. ^ Fries, K.; Finck, G. Ber. 1908, 41, 2447.
  2. ^ Fries, K.; Pfaffendorf, W. Ber. 1910, 43, 212.
  3. ^ March, J. Advanced Organic Chemistry, 3rd Ed.; John Wiley & Sons: Chichester, 1985; S. 499ff.
  4. ^ Bellus, D. Advances in Photochemistry; John Wiley & Sons: Chichester, 1971; Vol. 8, 109–159.

See also

 
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