Term: entering group
https://doi.org/10.1351/goldbook.E02130

Definition:
An atom or group that forms a bond to what is considered to be the main part of the substrate during a reaction. For example: the attacking nucleophile in a bimolecular nucleophilic substitution reaction.

Related Terms:
1) substrate (http://doi.org/10.1351/goldbook.S06082).
2) nucleophile (http://doi.org/10.1351/goldbook.N04249).
3) substitution reaction (http://doi.org/10.1351/goldbook.S06078).
4) bimolecular (http://doi.org/10.1351/goldbook.M03989).

Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1113 (https://doi.org/10.1351/pac199466051077)

Citation: 'entering group' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.E02130

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