Chugaev elimination

Named after  | Lev Chugaev
Reaction type  | Elimination reaction
Identifiers
RSC ontology ID  | RXNO:0000538

The Chugaev elimination is a chemical reaction that involves the elimination of water from alcohols to produce alkenes. The intermediate is a xanthate. It is named for its discoverer, the Russian chemist Lev Aleksandrovich Chugaev (1873-1922), who first reported the reaction sequence in 1899.

In the first step, a xanthate salt is formed out of the alkoxide and carbon disulfide (CS2). With the addition of iodomethane, the alkoxide is transformed into a methyl xanthate.

At about 200 °C, the alkene is formed by an intramolecular elimination. In a 6-membered cyclic transition state the hydrogen atom is removed from the carbon atom β to the xanthate oxygen in a syn-elimination. The side product decomposes to carbonyl sulfide (OCS) and methanethiol.

The Chugaev elimination is similar in mechanism to other thermal elimination reactions such as the Cope elimination and ester pyrolysis. Xanthates typically undergo elimination from 120 to 200 °C, while esters typically require 400 to 500 °C and amine oxides routinely react between 80 and 160 °C.

## See also

* Barton–McCombie deoxygenation

## References

* Latscha, Hans P. (2002). Chemie-Basiswissen. Berlin: Springer.
* L. Tschugaeff (1900). "Ueber das Thujen, ein neues bicyclisches Terpen". Berichte der deutschen chemischen Gesellschaft 33 (3): 3118–3126. doi:10.1002/cber.19000330363.

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Alkenes

Alkenes|

* Ethene ( C2H4 )
* Propene ( C3H6 )
* Butene ( C4H8 )
* Pentene ( C5H10 )
* Hexene ( C6H12 )
* Heptene ( C7H14 )
* Octene ( C8H16 )
* Nonene ( C9H18 )
* Decene ( C10H20 )

Preparations|

* Dehydrohalogenation from haloalkane
* Dehydration reaction from alcohol
* Semihydrogenation from alkyne
* Bamford–Stevens reaction
* Barton–Kellogg reaction
* Boord olefin synthesis
* Chugaev elimination
* Cope reaction
* Corey–Winter olefin synthesis
* Grieco elimination
* Hofmann elimination
* Horner–Wadsworth–Emmons reaction
* Hydrazone iodination
* Julia olefination
* Kauffmann olefination
* McMurry reaction
* Peterson olefination
* Ramberg–Bäcklund reaction
* Shapiro reaction
* Takai olefination
* Wittig reaction
* Olefin metathesis
* Ene reaction
* Cope rearrangement

Reactions|

* Hydrogenation
* Halogenation
* Hydration
* Electrophilic addition
* Oxymercuration reaction
* Hydroboration
* Cyclopropanation
* Epoxidation
* Dihydroxylation
* Ozonolysis
* Hydrohalogenation
* Polymerization
* Diels–Alder reaction
* Wacker process
* Dehydrogenation
* Ene reaction
* Friedel-Crafts Alkylation

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Topics in Organic Reactions

* Addition reaction
* Elimination reaction
* Polymerization
* Reagents
* Rearrangement reaction
* Redox reaction
* Regioselectivity
* Stereoselectivity
* Stereospecificity
* Substitution reaction

List of organic reactions

## External links

* Animation of the mechanism of the Chugaev elimination

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