Sommelet–Hauser rearrangement

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The Sommelet–Hauser rearrangement (named after M. Sommelet

aromatic ortho position. For example, benzyltrimethylammonium iodide, [(C6H5CH2)N(CH3)3]I, rearranges in the presence of sodium amide to yield the o-methyl derivative of N,N-dimethylbenzylamine.[2]

Sommelet-Hauser rearrangement

Mechanism

The benzylic methylene proton is acidic and deprotonation takes place to produce the benzylic ylide (1). This ylide is in equilibrium with a second ylide that is formed by deprotonation of one of the ammonium methyl groups (2). Though the second ylide is present in much smaller amounts, it undergoes a 2,3-sigmatropic rearrangement because it is more reactive than the first one and subsequent aromatization to form the final product (3).[5]

Sommelet-Hauser mechanism

The Stevens rearrangement is a competing reaction.

References

  1. ^ M. Sommelet, Compt. Rend. 205, 56 (1937).
  2. ^
    doi:10.1021/ja01153a022
  3. OCLC 642506595
  4. ^ Organic Syntheses, Coll. Vol. 4, p.585 (1963); Vol. 34, p.61 (1954) Link.
  5. ^ Ahluwalia, V. K., and R. K. Parashar. Organic Reaction Mechanisms. Harrow, U.K.: Alpha Science International, 2005. Print.
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