SN2 response

Area of ​​Expertise - Organic chemistry

In the case of nucleophilic substitution, a distinction is made between three different reaction processes: ${\text{S.}}_{\text{N}}1$ (monomolecular), ${\text{S.}}_{\text{N}}2$ (bimolecular) and SNI (internal nucleophilic substitution).

The nucleophilic substitution according to the ${\text{S.}}_{\text{N}}2$-Mechanism takes place in concert, i.e. bond breaking and bond formation occur simultaneously and a pentacoordinated transition state is passed through (exception ${\text{S.}}_{\text{N}}2$Reactions on carboxylic acid derivatives). The nucleophile attacks from the side opposite the leaving group. This leads to an inversion (Walden reversal) at a stereogenic center.

A ${\text{S.}}_{\text{N}}2$Mechanism is favored by sterically less demanding starting materials and substrates. Further factors are basicity and polarizability of the nucleophile, the neighboring group effect influencing the leaving group, the solvent and the reaction temperature.

See also: SN1 reaction

Learning units in which the term is dealt with

SN1 - First Order Nucleophilic Substitution45 min.

ChemistryOrganic chemistrysubstitution

The learning unit describes the first-order nucleophilic substitution (SN1 reaction). The parameters for influencing the reaction are also dealt with.

Nucleophilic substitution and its 3D visualization35 min.

ChemistryOrganic chemistrysubstitution

This learning unit deals with nucleophilic substitution. With the reaction visualization system CAVOC, the quantum mechanically calculated SN2 reaction can be viewed three-dimensionally. Further literature examples on nucleophilic substitution are offered and described.