Term: pro-E, pro-Z
https://doi.org/10.1351/goldbook.P04867

Definition:
One of a pair of identical groups c attached to a double bond (as in abC=Cc2) is described as pro-E if, when it is arbitrarily assigned CIP priority over the other group c, the stereodescriptor of the molecule becomes E. The other group c is then described as pro-Z.

Related Terms:
1) cip priority (http://doi.org/10.1351/goldbook.C01082).
2) stereodescriptor (http://doi.org/10.1351/goldbook.S05976).

Source: PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2214 (https://doi.org/10.1351/pac199668122193)

Citation: '<i>pro-E, pro-Z</i>' 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.P04867

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