University Chemistry ›› 2025, Vol. 40 ›› Issue (12): 187-191.doi: 10.12461/PKU.DXHX202510104

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Mechanistic Study of the Classic Hofmann Elimination Reaction

Hongyu Cheng1, Ruiyao Wang2, Xingwen Sun1   

  1. 1 Department of Chemistry, Fudan University, Shanghai 200433, China;
    2 High School Affiliated to Fudan University, Shanghai 200433, China
  • Received:2025-10-29 Accepted:2025-12-03 Published:2025-12-27
  • Contact: Xingwen Sun E-mail:sunxingwen@fudan.edu.cn

Abstract: This paper evaluates the mechanisms of the classic Hofmann elimination, especially the elimination reaction of cyclic quaternary ammonium hydroxide. When there are two trans-coplanar β-H, the hydrogen on the carbon with more substituents tends to be eliminated, resulting in the main product being an olefin with Zaitsev selectivity. This conclusion is also supported by DFT study result.

Key words: Quaternary ammonium hydroxide, Hofmann elimination, Zaitsev selectivity, Hofmann selectivity