Ethers from Alkenes: Alcohol Addition and Alkoxymercuration-Demercuration

In addition to the alcohol dehydration and the Williamson ether synthesis pathways, ethers can also be prepared from alkenes through the acid-catalyzed addition of alcohols and the alkoxymercuration–demercuration methods.

The acid-catalyzed addition of alcohols to alkenes involves treating an alkene with an excess of alcohol in the presence of an acid catalyst to form an ether under suitable conditions.

For example, 2-methylpropene and methanol, when passed over an acid catalyst, give 2-methoxy-2-methylpropane.

The reaction begins with a proton transfer from the acid catalyst to the alkene's π bond, forming a carbocation intermediate.

Next, the carbocation acts as an electrophile and reacts with the nucleophilic oxygen of a methanol molecule, forming an oxonium ion.

Finally, proton transfer from the oxonium ion to the methanol solvent completes the reaction, forming the ether.

Another method for the preparation of ethers is the alkoxymercuration–demercuration of alkenes.

Alkoxymercuration is a two-step process to produce ethers by reacting an alcohol with an alkene in the presence of a mercury salt, such as mercuric acetate, followed by demercuration with sodium borohydride.

The re