Title: stereoselectivity
Long Title: IUPAC Gold Book - stereoselectivity
DOI: 10.1351/goldbook.S05991
Status: current

Definition
The preferential formation in a chemical reaction of one stereoisomer over another. When the stereoisomers are enantiomers, the phenomenon is called 'enantioselectivity' and is quantitatively expressed by the enantiomeric excess; when they are diastereoisomers, it is called 'diastereoselectivity' and is quantitatively expressed by the diastereoisomer excess.

Related Terms
- diastereoisomer excess: https://goldbook.iupac.org/terms/view/D01675
- diastereoisomers: https://goldbook.iupac.org/terms/view/D01679
- enantiomeric excess: https://goldbook.iupac.org/terms/view/E02070
- stereoisomers: https://goldbook.iupac.org/terms/view/S05984

Source
- PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2219 (https://doi.org/10.1351/pac199668122193)

Related Reference
- PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1167 (https://doi.org/10.1351/pac199466051077)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/S05991/html
- json: https://goldbook.iupac.org/terms/view/S05991/json
- xml: https://goldbook.iupac.org/terms/view/S05991/xml

Citation: Citation: 'stereoselectivity' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.S05991
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Accessed: 2026-06-28T22:24:08+00:00