The Wagner-Meerwein rearrangement uses catalytic acid to convert an alcohol into an olefin. The alcohol is protonated and released as water to form a carbocation. A [1,2]-shift of an adjacent carbon-carbon bond generates a more stable carbocation, followed by loss of a proton to afford the alkene. Both E/Z products are possible in some cases.

• Reagents: Catalytic Acid
• Reactant: Alcohol
• Product: Olefin
• Type of Reaction: Carbocation Rearrangement
• Bond Formation: C=C

Lab Tips

• The initial carbocation can be generated via treatment of an alkyl halide with a Lewis acid, solvolysis of a secondary or tertiary alkyl halide, protonation of an alkene, etc.
• The [1,2][1,2]-shifts may be necessary to generate the most stable carbocation.
• Several products may arise if more than one rearrangement pathway is possible.
• The stereochemistry of the migrating group is retained (Woodward-Hofmann rules).
• A nucleophile present in the reaction mixture (i.e. the solvent or the conjugate base of the acid used to promote the rearrangement) may capture the carbocation forming a substituted product instead.

Mechanism

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Related Reactions

Related Compounds