Perkin reaction
Template:Short description Template:Distinguish Template:Use dmy dates Template:Reactionbox 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.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> The alkali salt acts as a base catalyst, and other bases can be used instead.<ref>Template:Cite journal</ref>
Several reviews have been written.<ref>Template:Cite journal</ref><ref>House, H. O. (1972) Modern Synthetic Reactions, W. A. Benjamin, Menlo Park, California, 2nd ed, pp. 660–663</ref><ref>Template:Cite journal</ref>
Reaction mechanismEdit
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.<ref>Bansal, Raj K. (1998) Organic Reaction Mechanisms, Tata McGraw Hill, 3rd Edition , pp. 199–201, Template:ISBN {{#invoke:doi|main}}.</ref>
ApplicationsEdit
- Salicylaldehyde converted to coumarin using acetic anhydride with acetate as base.<ref name=Ullmann>Template:Cite book</ref>
- 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.<ref name="SolladiéPasturel-Jacopé2003">Template:Cite journal</ref>