"The principal olefin formed in the @[email protected] of quaternary ammonium hydroxides that contain different primary @[email protected] is always ethylene, if an ethyl group is present." Originally given in this limited form by A. W. Hofmann, the rule has since been extended and modified as follows: "When two or more @[email protected] can be produced in a β[email protected]@ reaction, the alkene having the smallest number of @[email protected] attached to the double bond carbon atoms will be the predominant product." This orientation described by the Hofmann rule is observed in @[email protected] reactions of quaternary ammonium salts and tertiary sulfonium salts, and in certain other cases.
See also:
Zaitsev rule
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1121 [Terms] [Paper]