11.4: Ethers from Alkenes: Alcohol Addition and Alkoxymercuration-Demercuration
Ethers can also be prepared from alkenes through acid-catalyzed addition of alcohols and alkoxymercuration–demercuration.
Preparation of Ethers by Acid-Catalyzed Addition of Alcohol to Alkenes
The acid-catalyzed addition of alcohol to an alkene involves treating the alkene with an excess of alcohol in the presence of an acid catalyst to form an ether under suitable conditions. The hydrogen will add to the less substituted carbon so that the nucleophile can attack the more substituted carbon across an alkene forming an ether.
Preparation of Ethers by Alkoxymercuration–Demercuration
Alkoxymercuration–demercuration is a reaction in which an alkene and alcohol react in the presence of a mercuric acetate reagent followed by demercuration or reduction with sodium borohydride to yield an ether.
The alkoxymercuration–demercuration mechanism follows Markovnikov's regioselectivity with the alkoxy group attached to the most substituted carbon and the H attached to the least substituted carbon. A variety of alcohols and alkenes can be used in the reaction. Ditertiary ethers cannot be prepared by this method due to steric hindrance.