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SN/E Competition (overall)

ChemieOrganische ChemieSubstitution

First, this learning unit describes the mechanistic reasons for the competition of elimination and nucleophilic substitution. Then, the different parameters that influence the SN2/E2 competition as well as the SN1/E1 competition are discussed. After working through the learning unit, one should be able to predict, depending on given parameters, the predominant mechanism of a reaction or to choose the parameters of a reaction, so that a mechanism desired actually mainly occurs, respectively.


  • Prof. Dr. Gregor Fels
  • Dr. Carsten Biele


  • Dr. Carsten Biele

Learning objective

  • Fundamentals of the competition of elimination and nucleophilic substitution.
  • Parameters that influence the SN2/E2 competition.
  • Parameters that influence the SN1/E1 competition.
  • Prediction of the predominant reaction mechanism depending on the different parameters.

Important Keywords in this Learning Unit

elimination, transition state, reaction rate, nucleophile, carbenium ion