Darzens Condensation

Definition:

Formation of a,ß-epoxy esters by the condensation of aldehydes or ketones with esters of a-haloacids.:

Frequency of appearance:

        This bar graph represents all of the online articles that were found to contain this specific name reaction in the title of the article. Tetrahedron letters, Tetrahedron, Synthetic letters, Synthesis, Journal of Organic Chemistry and Journal of the American Chemical Society are represented here. This table by no means represents the periodicity of the name reaction found in the literature.

Original References:

1. Darzens, G. Compt. Rend., 1904, 139, 1214.
2. Darzens, G. Compt. Rend., 1906, 142, 214.

Recent academic references: Click here for more references

3. Camphor-Based Bromo Ketones for the Asymmetric Darzens Reaction

• Palomo, C.; et al., J. Org. Chem.; 2000; 65(26); 9007-9012.

4. Inverted Diastereoselectivity in Asymmetric Aziridine Synthesis via Aza-Darzens Reaction of (2S)-N-Bromoacyl Camphorsultam

• McLaren, A. B.; et al., Org. Lett.; 1999; 1(9); 1339-1341.

5. A Cyclic Transition State for the Darzen Reaction

• Yliniemela, A.; et al., J. Org. Chem.; 1996; 61(19); 6723-6726.  

6. http://www.rhodium.ws/chemistry/2ch.darzen.html

Recent process references:

Mechanism: http://www.arkat.org/arkat/journal/Named Reactions/Darzens.htm

Scope and Limitations:

• Good yields with aromatic aldehydes and ketones. ^A+B
• Aliphatic aldehydes need the aid of LDA or LiN(SiMe3)2 to 1st deprotonate the alpha halo ester to obtain high yields. ^A+B
• alpha-halo ketones, nitriles, sulphones and N,N-amides are also used for Darzen's condensation. ^A+B
• Na ethoxide is often employed as a base. ^A
• Reaction can also be catalyzed by an acid. ^A

Synonyms: