The Chugaev reaction allows the formation of olefins from xanthans.

reaction chugaev 01

It is a pyrolysis reaction that is generally carried out in the temperature range between 100 and 250ºC.
Methyl xanthate can be prepared by reaction of the deprotonated alcohol with carbon disulfide followed by alkylation with methyl iodide.
reaction chugaev 02
The mechanism is similar to that of ester pyrolysis and involves a six-membered cyclic transition state. The reaction is stereospecific syn.
reaction chugaev 03