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