Annulation
Template:Short description Script error: No such module "Distinguish".
In organic chemistry, annulation (Script error: No such module "params".; occasionally annelation) is a chemical reaction in which a new ring is constructed on a molecule.[1]
Examples are the Robinson annulation, Danheiser annulation and certain cycloadditions. Annular molecules are constructed from side-on condensed cyclic segments, for example helicenes and acenes. In transannulation a bicyclic molecule is created by intramolecular carbon-carbon bond formation in a large monocyclic ring. An example is the samarium(II) iodide induced ketone - alkene cyclization of 5-methylenecyclooctanone which proceeds through a ketyl intermediate:[2]
Benzannulation
The term benzannulated compounds refers to derivatives of cyclic compounds (usually aromatic) which are fused to a benzene ring. Examples are listed in the table below:
| Benzannulated derivative | Source of cyclic compound |
|---|---|
| Benzopyrene | Pyrene |
| Quinoline | Pyridine |
| Isoquinoline | |
| Chromene | Pyran |
| Isochromene | |
| Indole | Pyrrole |
| Isoindole | |
| Benzofuran | Furan |
| Isobenzofuran | |
| Benzimidazole | Imidazole |
In contemporary chemical literature, the term benzannulation also means "construction of benzene rings from acyclic precursors".[3]
Transannular interaction
A transannular interaction in chemistry is any chemical interaction (favorable or nonfavorable) between different non-bonding molecular groups in a large ring or macrocycle.[5] See for example atranes.
References
Page Template:Reflist/styles.css has no content.
- ^ IUPAC, Compendium of Chemical Terminology, 5th ed. (the "Gold Book") (2025). Online version: (2006–) "annulation". Script error: No such module "CS1 identifiers".IUPAC, Compendium of Chemical Terminology, 5th ed. (the "Gold Book") (2025). Online version: (2006–) "annelation". Script error: No such module "CS1 identifiers".
- ^ Construction of Bicyclic Ring Systems via a Transannular SmI2-Mediated Ketone-Olefin Cyclization StrategyGary A. Molander, Barbara Czakó, and Michael Rheam J. Org. Chem.; 2007; 72(5) pp 1755 - 1764; (Article) Script error: No such module "CS1 identifiers".
- ^ Page Module:Citation/CS1/styles.css has no content.Swami, Bhawna; Yadav, Deepak; Menon, Rajeev S. (January 2022). "Benzannulation Reactions: A Case for Perspective Change From Arene Decoration to Arene Construction". The Chemical Record. 22 (1) e202100249. doi:10.1002/tcr.202100249. ISSN 1527-8999. PMID 34796605. S2CID 244403005.
- ^ Page Module:Citation/CS1/styles.css has no content.Verkade, John G.; Urgaonkar, Sameer (2012). "Proazaphosphatrane". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn00702.pub2. ISBN 978-0-471-93623-7.
- ^ Experimental evidence in support of transannular interactions in diketones Kata Mlinaric-Majerski, Marijana Vinkovic, Danko Škare, Alan P. Marchand Arkivoc DS-339E 2002 Online Article Script error: No such module "webarchive".
