Elimination reaction
Organic reaction removing substituents to form a pi bond.
Last updated
An elimination reaction removes two substituents from a molecule in either a one-step or two-step mechanism.[1] The most common type is β-elimination, which involves loss of groups from vicinal carbon atoms.[2]
Last updated 2026-10-01 from the source article.
Quick Facts
- Type
- Organic reaction type
- Common mechanisms
- E2
- E1
- E1CB
- Ei
- Key feature
- Loss of sigma bonded groups to form a pi bond
- Typical products
- Alkenes from alkanes
- Competing reactions
- SN2, SN1
Facts from the source article.
Key facts and history
The E2 reaction is a one-step mechanism, while the E1 reaction proceeds in two steps.[1] β-Elimination is strongly favored by the ability to form a stable C=C or C=X bond and by orbital alignment.[2] When β-elimination cannot occur, other types such as α-elimination are known.[2] α-Elimination from a carbon center produces a carbene, including stable carbenes like carbon monoxide.[3]
A classic example of α-elimination is the generation of dichlorocarbene from chloroform and strong base.[3] Formic acid undergoes α-elimination under acidic conditions to yield water and carbon monoxide.[3] In organometallic chemistry, α-elimination on a metal center can lower the metal oxidation state and coordination number by two in reductive elimination.[3] γ- and higher eliminations can form three-membered or larger rings in both organic and organometallic processes.[4]
Strained bicyclic systems have been prepared more recently by applying γ-silyl elimination to a silylcyclobutyl tosylate.[4]
References
- Wikipedia, "Elimination reaction" (CC BY-SA 4.0) en.wikipedia.org
- Wikipedia, "Elimination reaction" (CC BY-SA 4.0), which cites: Anslyn, Eric V., "Modern physical organic chemistry", University Science, 2006 (we also read that source) en.wikipedia.org
- Wikipedia, "Elimination reaction" (CC BY-SA 4.0), which cites: Crabtree, Robert H., "The organometallic chemistry of the transition metals", Wiley, 2009 (we also read that source) en.wikipedia.org
- Wikipedia, "Elimination reaction" (CC BY-SA 4.0), which cites: Moore, "Ring strain in bis(triethylphosphine)-3,3-dimethylplatinacyclobutane is small", Journal of the American Chemical Society, 1981-02-01, p. 948–949; Kelly, "Enabling the Synthesis of Perfluoroalkyl Bicyclobutanes via 1,3 γ-Silyl Elimination", Organic Letters, 2011-04-01, p. 1646–1649 (we also read that source) en.wikipedia.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Elimination reaction (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Elimination reaction (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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