Perkin reaction
Organic reaction developed by William Henry Perkin
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The Perkin reaction is an organic reaction developed by English chemist William Henry Perkin in 1868 that is used to make cinnamic acids. It gives an α,β-unsaturated aromatic acid or α-substituted β-aryl acrylic acid by the aldol condensation of an aromatic aldehyde and an acid anhydride, in the presence of an alkali salt of the acid.[1][2] The alkali salt acts as a base catalyst, and other bases can be used instead.[3]
| Perkin reaction | |||||||||||
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| Named after | William Henry Perkin | ||||||||||
| Reaction type | Condensation reaction | ||||||||||
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| RSC ontology ID | RXNO:0000003  | ||||||||||
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Reaction mechanism
Clear from the reaction mechanism, the anhydride of aliphatic acid must contain at least 2 α-H for the reaction to occur. The above mechanism is not universally accepted, as several other versions exist, including decarboxylation without acetic group transfer.[7]
Applications
- Salicylaldehyde converted to coumarin using acetic anhydride with acetate as base.[8]
- cinnamic acid is prepared from benzaldehyde, again using acetic anhydride in the presence of sodium or potassium acetate.
- resveratrol (cf. fo-ti), a phytoestrogenic stilbene is yet another product of this methodology.[9]