Rearrangement of Beckmann

See also: Beckmann

In Organic chemistry, the Réarrangement of Beckmann is a reaction making it possible to convert a Oxime into Amide and implies the migration of a grouping alkyl on a Azote returned électrophile (low in electron).

This reaction rests on the conversion of the Groupement hydroxyl of oxime into a grouping leaving using an acid (of Lewis or not), of a Anhydride or a Halogénure of acyle.

Mechanism

The Groupement hydroxyl of oxime is first of all converted into grouping leaving using X+. The ionization and migration of the grouping - R take place then during a Processus concerted : it is thus the grouping - R in anti compared to the hydroxyl group of the function oxime (and not - R') which migrates. One then obtains an ion nitrillium which will capture a Nucléophile (HOY), and the intermédiare obtained will then be converted into amide during the hydrolysis.

References

  1. E. Beckmann, Ber. 19,988 (1886)

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