**Annulenes are the completely conjugated monocyclic hydrocarbons containing an even number of carbon atoms. They have the general formula CnHn (when n is an even number) or Cn.Hn+1 (when n is an odd number)
**The first 3 members of the series, (4]-, [6]-, and [8]-annulene but you must have used their name as 1,3- cyclobutadiene, benzene and 1,3,5,7- cyclooctatetraene.
**Annulenes could be aromatic, anti aromatic or non-aromatic.
#[4] Annulene: anti-aromatic
#[6] Annulene: aromatic
#[81 Annulene: non-aromatic
#[10] Annulene: non-aromatic
#[12] Annulene anti-aromatic
#[14] Annulene: anti-aromatic.
#[18] Annulene: aromatic.
**The following bridgehead [10] annulenes are aromatic:
#9,10 methane [10] annulene
#9,10 oxa [10] annulerne
#9,10 aza [10] annulene
**Preparation of [14] annulene, [18] annulene and 9,10-methane [10] annulene from simple and easily available molecules.