Hofmann Elimination

Abstract

The thermal decomposition of tetraalkylammonium hydroxide to form an olefin and a tertiary amine is generally known as the Hofmann elimination. As the nature of pyrolysis, the Hofmann elimination is often carried out in a solvent with a high boiling point. The anti‐elimination predominates on six‐membered rings. However, a few exceptions that proceed E2 elimination via the cis transition state are also known due to the enhanced acidity of proton, or conformational or steric hindrance. Furthermore, the eclipsing effects of substituents and the van der Waals interaction with bulky trimethylammonium groups can alter the mechanism as well. In addition, it has been reported that the proton transfer in the transition state is greater in the syn elimination than that in the anti ‐elimination. The Hofmann elimination has been applied extensively for the structural elucidation of alkaloids and analysis of alkylbenzyldimethylammonium chloride (ABDAC). This reaction has also been extended to resin for the preparation of tertiary amine library.