Chugaev elimination

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 1873, Moscow, died 9 October 1922.



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.



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 &beta;-C-atom to the sulfur. The side product decomposes to carbonyl sulfide (OCS) and methanethiol.



Reference
Latscha, Hans P. Chemie-Basiswissen. Berlin(2002): Springer.

Tschugajew-Reaktion シュガエフ脱離 Chugaev-reactie