Chemical Sciences: A Manual for CSIR-UGC National Eligibility Test for Lectureship and JRF/Named Reactions/Sommelet-Hauser Rearrangement

The Sommelet-Hauser rearrangement is a rearrangement reaction of certain benzyl quaternary ammonium salts [1]. The reagent is sodium amide or another alkali metal amide and the reaction product a N-dialkyl benzyl amine with a new alkyl group in the aromatic ortho position.

Sommelet-Hauser rearrangement

This reaction was named after M. Sommelet [2] and Charles R. Hauser [3]


The benzylic methylene proton is acidic and deprotonation takes place to the ylide. The second step is a 2,3-sigmatropic rearrangement.



  1. Organic Syntheses, Coll. Vol. 4, p.585 (1963); Vol. 34, p.61 (1954) Link.
  2. M. Sommelet, Compt. Rend. 205, 56 (1937).
  3. Rearrangements of Benzyltrimethylammonium Ion and Related Quaternary Ammonium Ions by Sodium Amide Involving Migration into the Ring Simon W. Kantor, Charles R. Hauser J. Am. Chem. Soc., 1951, 73 (9), pp 4122–4131 doi:10.1021/ja01153a022