Term: diastereotopic
https://doi.org/10.1351/goldbook.D01685

Definition:
Constitutionally equivalent atoms or groups of a molecule which are not symmetry related. Replacement of one of two diastereotopic atoms or groups results in the formation of one of a pair of diastereoisomers. In the example below the two hydrogen atoms of the methylene group C-3 are diastereotopic. D01685.png

Related Terms:
1) prochirality (http://doi.org/10.1351/goldbook.P04859).
2) enantiotopic (http://doi.org/10.1351/goldbook.E02083).
3) heterotopic (http://doi.org/10.1351/goldbook.H02815).
4) diastereoisomers (http://doi.org/10.1351/goldbook.D01679).
5) methylene (http://doi.org/10.1351/goldbook.M03881).

Image: Not defined (https://goldbook.iupac.org/img/inline/D01685.png) 

Source: PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2206 (https://doi.org/10.1351/pac199668122193)

Citation: 'diastereotopic' 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.D01685

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