Acid-catalyzed alkoxylation is a method for synthesizing ethers that closely resembles acid-catalyzed hydration, with the key difference being the use of an alcohol as the nucleophile instead of water. This process begins with a double bond, which acts as a good nucleophile, and a strong acid, such as sulfuric acid.

The mechanism initiates when the nucleophile (the alcohol) attacks a proton from the strong acid, forming a carbocation. This carbocation can undergo a rearrangement, typically a methyl or hydride shift, to achieve a more stable configuration. In this case, a methyl shift occurs, moving a methyl group to stabilize the carbocation, resulting in a tertiary carbocation.

Next, the alcohol nucleophile attacks the carbocation, leading to the formation of an ether. Instead of producing an alcohol as in hydration, the product here is an ether represented as R-O-R, where R denotes the alkyl groups derived from the original double bond and the alcohol. The oxygen in the ether will carry a formal charge, which can be neutralized by deprotonation using the conjugate base of the sulfuric acid, yielding the final ether product and regenerating the sulfuric acid.

This reaction highlights the importance of carbocation stability and the role of rearrangements in organic synthesis. Understanding this mechanism is crucial for mastering ether formation and its applications in organic chemistry.