Title: protecting group
Long Title: IUPAC Gold Book - protecting group
DOI: 10.1351/goldbook.09560
Status: current

Definition
Non-reactive group temporarily used to transform a reactive group into one that does not react under conditions where the non-protected group reacts.

Notes
1) Trimethylsilylation is a typical transformation used to protect reactive functional groups, such as hydroxy or amino groups, from their reaction with the propagating species in an anionic polymerization.
2) In photoresists, protecting groups may also alter solubility (e.g., tBOC protection of hydroxy groups in chemically amplified poly(4-hydroxystyrene) resists).

Related Term
- resists: https://goldbook.iupac.org//terms/view/09564

Source
- PAC, 2020, 92, 1861. 'Terminology of polymers in advanced lithography (IUPAC Recommendations 2020)' on page 1885 (https://doi.org/10.1515/pac-2018-1215)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09560/html
- json: https://goldbook.iupac.org/terms/view/09560/json
- xml: https://goldbook.iupac.org/terms/view/09560/xml

Citation: Citation: 'protecting group' 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.09560
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Accessed: 2026-06-20T14:57:45+00:00