Perkin reaction
{{Short description|Organic reaction developed by William Henry Perkin}}
{{distinguish|Perkin rearrangement}}
{{Use dmy dates|date=January 2024}}
{{Reactionbox
|verifiedrevid = 342064841
|Type = Condensation reaction
|NamedAfter = William Henry Perkin
|Section2 = {{Reactionbox Identifiers
|RSC_ontology_id_verified = rsccite
|RSC_ontology_id = 0000003
}}
|Reaction = {{Reactionbox Reaction
|Reactant1 = Aromatic aldehyde
|Reactant2 = Aliphatic acid anhydride
|Reagent1 = Alkali salt of the acid
|Product1 = Cinnamic acid derivatives
}}
}}
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.{{cite journal|author=Perkin, W. H.|journal=Journal of the Chemical Society|year=1868|volume=21|pages= 53–61|doi=10.1039/js8682100053|title= On the artificial production of coumarin and formation of its homologues|url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015077817479;view=1up;seq=65}}{{cite journal|author=Perkin, W. H.|journal=Journal of the Chemical Society|year=1877|volume=32|pages= 660–674|doi=10.1039/js8773200660|title= On some hydrocarbons obtained from the homologues of cinnamic acid; and on anethol and its homologues|url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015077817446;view=1up;seq=1444}} The alkali salt acts as a base catalyst, and other bases can be used instead.{{cite journal |title= The nature of the catalyst in the Perkin condensation |first1= J. F. J. |last1= Dippy |first2= R. M. |last2= Evans |journal= J. Org. Chem. |year= 1950 |volume= 15 |issue= 3 |pages= 451–456 |doi= 10.1021/jo01149a001}}
Several reviews have been written.{{cite journal|author=Johnson, J. R.|journal=Org. React.|year=1942|volume=1|pages= 210–265|doi=10.1002/0471264180.or001.08|title=The Perkin Reaction and Related Reactions|isbn=0471264180}}House, H. O. (1972) Modern Synthetic Reactions, W. A. Benjamin, Menlo Park, California, 2nd ed, pp. 660–663{{cite journal|author=Rosen, T.|journal=Compr. Org. Synth.|year=1991|volume=2|pages= 395–408|doi=10.1016/B978-0-08-052349-1.00034-2|title=The Perkin Reaction|isbn=978-0-08-052349-1}}
Reaction mechanism
Image:Perkin reaction mechanism.svg
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.Bansal, Raj K. (1998) Organic Reaction Mechanisms, Tata McGraw Hill, 3rd Edition , pp. 199–201, {{ISBN|9780470858585}} {{doi|10.1002/0470858583}}.
Applications
- Salicylaldehyde converted to coumarin using acetic anhydride with acetate as base.{{cite book |doi=10.1002/14356007.t11_t02 |chapter=Flavors and Fragrances, 3. Aromatic and Heterocyclic Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2016 |last1=Panten |first1=Johannes |last2=Surburg |first2=Horst |pages=1–45 |isbn=978-3-527-30673-2 }}
- cinnamic acid is prepared from benzaldehyde, again using acetic anhydride in the presence of sodium or potassium acetate.
- resveratrol (c.f. fo-ti), a phytoestrogenic stilbene is yet another product of this methodology.{{cite journal|last1=Solladié|first1=Guy|last2=Pasturel-Jacopé|first2=Yacine|last3=Maignan|first3=Jean|title=A re-investigation of resveratrol synthesis by Perkins reaction. Application to the synthesis of aryl cinnamic acids|journal=Tetrahedron|volume=59|issue=18|year=2003|pages=3315–3321|issn=0040-4020|doi=10.1016/S0040-4020(03)00405-8}}