Cyanohydrin reaction
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Addition reaction of carbonyl compounds and cyanide
| Cyanohydrin reaction | |
|---|---|
| Named after | Friedrich Urech |
| Reaction type | Addition reaction |
A cyanohydrin reaction is an
carbonyl compounds equilibrium is in favor of the reaction products. The cyanide source can be potassium cyanide, sodium cyanide or trimethylsilyl cyanide. With aromatic aldehydes such as benzaldehyde, the benzoin condensation is a competing reaction. The reaction is used in carbohydrate chemistry as a chain extension method for example that of D-xylose
.
Examples
Reaction mechanism
Asymmetric synthesis
The
catalyst loading. This ligand
firsts reacts with a lithium alkoxy compound to form a lithium binaphtholate Complex.
Binol–lithium(i-propyloxy) gives (S)-acetonitrile with 98% ee
Asymmetric reaction of benzaldehyde with (R)–
Binol–lithium(i-propyloxy) gives (S)-acetonitrile with 98% ee
The chemist Urech in 1872 was the first to synthesize cyanohydrins from ketones with alkali cyanides and acetic acid[2] and therefore this reaction also goes by the name of Urech cyanohydrin method.
References
- PMID 16076152.
- .
External links
- Cyanohydrin reaction of formaldehyde to hydroxyacetonitrile or glycolonitrile with sodium cyanide in Organic Syntheses Coll. Vol. 2, p. 387; Vol. 13, p. 56 Article
- Cyanohydrin reaction of formaldehyde with potassium cyanide Organic Syntheses Coll. Vol. 3, p. 436; Vol. 27, p. 41 Article
- Cyanohydrin reaction of acetophenone with potassium cyanide Organic Syntheses Coll. Vol. 4, p. 58; Vol. 33, p. 7 Article
- Cyanohydrin reaction of D-xylose with potassium cyanide Organic Syntheses Coll. Vol. 4, p. 506; Vol. 36, p. 38 Article
- Cyanohydrin reaction of acetone with potassium cyanide Organic Syntheses Coll. Vol. 2, p. 7; Vol. 15, p. 1 Article
- Cyanohydrin reaction of benzoquinone with trimethylsilylcyanide Organic Syntheses Coll. Vol. 7, p. 517; Vol. 60, p. 126 Article