Neber rearrangement

The Neber rearrangement is a name reaction in organic chemistry . It is used to produce α-amino ketones from ketones . It is named after the German chemist Peter Neber (1883–1960) who discovered it in 1926. In fact, it is not a rearrangement , as was thought at the time of the discovery, but an amination .

Reaction mechanism

For this purpose, the ketone is first converted to the oxime with hydroxylamine . The oxygen atom of the oxime is then reacted with p -toluenesulfonic acid chloride to give the tosylate . For deprotonation of the hydroxy group is a base , such as pyridine are used. The tosylated oxime obtained in this way is reacted in the next step with a strong base which removes the C, H-acidic proton in the α-position to the oxime. For example, alcoholates such as sodium methoxide or sodium ethoxide are suitable as bases . The carbanion formed in this way now attacks the nitrogen of the oxime nucleophilically , with a tosylation, as a good leaving group , emerging from the molecule . The thus-formed derivative of azirine can now hydrolyzed to give the desired aminated arises ketone.

swell

• LM Harwood: Polar Rearrangements . 1st edition, VCH Weinheim 1995, ISBN 3-527-29291-8 .

Individual evidence

1. ^ PW Neber, Adolf v. Friedolsheim: About a new kind of rearrangement of oximes. In: Liebigs Ann. 1926, 449, 109-134.
2. ^ Neber rearrangement - Lexicon of Chemistry . ( Spektrum.de [accessed on March 15, 2017]).
3. ↑ Chemistry Online - Name Reactions - Neber rearrangement. Retrieved March 15, 2017 .