Nierenstein reaction

Nierenstein reaction
Named after	Maximilian Nierenstein
Reaction type	Carbon-carbon bond forming reaction

The Nierenstein reaction is an organic reaction describing the conversion of an acid chloride into a haloketone with diazomethane. ^{[1] [2]} It is an insertion reaction in that the methylene group from the diazomethane is inserted into the carbon-chlorine bond of the acid chloride.

The Nierenstein reaction

Reaction mechanism

The reaction proceeds through a diazonium salt intermediate formed when diazomethyl anion displaces the chloride:

The Nierenstein reaction mechanism

Excess diazomethane can act as a base, abstracting a hydrogen from the diazonium intermediate. The results are a neutral diazoketone, which does not react further; and methyldiazonium chloride, which decomposes to chloromethane. The unreactive diazoketone can, however, be re-activated with hydrogen chloride to give the Nierenstein product:

The Nierenstein reaction mechanism

In even some cases with limited diazomethane, the reaction process can stall into the diazoketone pathway, requiring reparative HCl gas. ^[3]

Examples

Nierenstein's original 1924 publication: ^[4]

Nierenstein 1924

A reaction from benzoyl bromide going haywire and forming the dioxane dimer: ^[5]

Nierenstein 1924

See also

• Maximilian Nierenstein
• Curtius rearrangement
• Wolff rearrangement
• Arndt–Eistert reaction: where acid chlorides react with diazomethane to give chain extended carboxylic acids via a rearrangement

References

1. Clibbens, D.; Nierenstein, M. (1915). "The action of diazomethane on some aromatic acyl chlorides". J. Chem. Soc. 107: 1491. doi:10.1039/CT9150701491.
2. Bachman, W. E.; Struve, W. S. (1942). "The Arndt-Eistert Reaction". Org. React. 1: 38. (Review)
3. McPhee, W. D; Klingsberg, E. Organic Syntheses , Coll. Vol. 3, p.119 (1955); Vol. 26, p.13 (1946). (Article)
4. M. Nierenstein; D. G. Wang & J. C. Warr (1924). "The Action of Diazomethane on some Aromatic Acyl Chlorides II. Synthesis of Fisetol". J. Am. Chem. Soc. 46 (11): 2551–2555. Bibcode:1924JAChS..46.2551N. doi:10.1021/ja01676a028.
5. H. H. Lewis; M. Nierenstein & Enid M. Rich (1925). "The Action of Diazomethane on some Aromatic Acyl Chlorides III. The Mechanism of the Reaction". J. Am. Chem. Soc. 47 (6): 1728–1732. Bibcode:1925JAChS..47.1728L. doi:10.1021/ja01683a036.