Cyclooctadecanonaene

Cyclooctadecanonaene

Identifiers
3D model (JSmol)	Interactive image
ChemSpider	120988 N
PubChem CID	137294
InChI InChI=1S/C18H18/c1-2-4-6-8-10-12-14-16-18-17-15-13-11-9-7-5-3-1/h1-18H/b2-1-,3-1+,4-2+,5-3+,6-4+,7-5-,8-6-,9-7+,10-8+,11-9+,12-10+,13-11-,14-12-,15-13+,16-14+,17-15+,18-16+,18-17- N Key: STQWAGYDANTDNA-DWSNDWDZSA-N N InChI=1/C18H18/c1-2-4-6-8-10-12-14-16-18-17-15-13-11-9-7-5-3-1/h1-18H/b2-1-,3-1+,4-2+,5-3+,6-4+,7-5-,8-6-,9-7+,10-8+,11-9+,12-10+,13-11-,14-12-,15-13+,16-14+,17-15+,18-16+,18-17- Key: STQWAGYDANTDNA-DWSNDWDZBB
SMILES c\1c/cc\cc\cc\cc/cc/cc/cc/cc1
Properties
Chemical formula	C18H18
Molar mass	234.34 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Cyclooctadecanonaene or [18]annulene is an annulene with chemical formula C
18H
18. This hydrocarbon obeys Hückel's rule and is, therefore, an aromatic compound. Theoretical studies show that [18]annulene has only three completely delocalized π bonds associated with its aromaticity, while other six π bonds represent the conjugated 3c-2e π bonds on the periphery of [18]annulene. The compound was first synthesised by Franz Sondheimer.

The original synthesis started by the Eglinton reaction of the di-alkyne 1,5-hexadiyne with copper(II) acetate in pyridine to give the trimer, followed by deprotonation and isomerization with potassium tert-butoxide in tert-butanol and was concluded with hydrogen organic reduction with the Lindlar catalyst.