Hoffmann elimination of alkylammonium salts to give alkenes

Description: Tetra-alkyl ammonium salts undergo elimination to form the least substituted alkene. This is called the Hoffman elimination

Notes: For the elimination step, silver oxide (Ag2O) is a common base for this purpose, although other strong bases such as hydroxide ion (e.g. NaOH) can be used.

Examples:

Notes: Note that the second example also shows the alkylation step (using MeI)

Mechanism: This is an elimination reaction. The strong base removes a proton from the carbon adjacent to the bulky leaving group on the least substituted carbon, resulting in formation of the double bond (Step 1, arrows A, B, and C)

Notes: Note how the extra steric interactions between the leaving group and the alkyl group on the more substituted carbon destabilizes the Zaitsev transition state