annulation

https://doi.org/10.1351/goldbook.A00367
A transformation involving fusion of a new ring to a molecule via two new bonds. Some authors use the term 'annelation' for the fusion of an additional ring to an already existing one, and 'annulation' for the formation of a ring from one or several acyclic precursors, but this distinction is not made generally.
See also: cyclization
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1083 [Terms] [Paper]
Citation: 'annulation' 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.A00367 RIS BibTex EndNote
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Last revised: October 7, 2008