Chugaev elimination

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The Chugaev elimination is a chemical reaction that involves the elimination of water from primary alcohols to produce terminal alkenes. The intermediate is a xanthate. It is named for the Russian chemist Lev Aleksandrovich Chugaev (a.k.a. Leo Aleksandrovich Tschugaeff), born 16 October [O.S. 4 October] 1873, Moscow, died 9 October [O.S. 26 September] 1922.

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In the first step, a potassium xanthate is formed out of the alkoxide and carbon disulfide (CS2). With iodomethane, it is transformed into a thioester.

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

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Reference

Latscha, Hans P. Chemie-Basiswissen. Berlin(2002): Springer.de:Tschugajew-Reaktionnl:Chugaev-reactie


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