Annulenes, annuleno

S. Nikobc and N. Trinajstic, Compact molecular codes for annulenes, aza-annulenes, annuleno-annulenes, aza-annulenoannulenes, cyclazines and aza-cyclazines, Croat. Chem. Acta 63 (1990) 155-169. 

We close this chapter with a brief discussion of [n]annuleno[n ]annulenes, those species composed of two ortfio-fused annulenes. Using the same closed shell criterion as for... 

Fig- 16 Generation of the sequence of nonadjacent numbers of 18-annuleno-18-annulene by starting three fibonacci internal subdivisions-... 

Recently, the bicyclic system [14]annuleno[14]annulene (20) was charged97. This system forms a dianion, viz. 202 and a tetraanion, viz. 20A studied by Mullen 97). This annuleno annulene is a (4n. + 2)n + (4n + 2)it system and therefore diatropic. The di- and tetra-anions of 20 can be related to the octalene system (14)901. The annulenoannulene 20 forms upon alkali metal (Li, K) reduction all intermediate... 

Ebe, H., Nakagawa, T., lyoda, M., and Nakagawa, M., Syntheses of an isoannulated annulene, a ftMdehydro[14]annuleno[c]furan and Z>Bdehydro[14]annulene derivatives. Tetrahedron Lett., 22,4441, 1981. 

J., Synthesis and properties of a bisdehydro[14]annuleno[c]furan and an ortho-annelated tetrakisde-hydro[ 14]annuleno[ 14]annulene. Bull. Chem. Soc. Jpn., (CI, JH, 1994. 

An ingenious synthesis of steroidal annulenes has appeared. The close relationship of annulenes to the classical aromatic substance naphthalene stimulated the synthesis of l,6-methano-[10]annuleno-steroids, which are analogues of equilenin (97). The y,5-cyclopropyl-a -unsaturated ketone (98) was the initial target. Treatment of the cyclopropyl ketone (98) with acetic anhydride and methyl orthoformate in the presence of an acid catalyst then gave (99). Conversion of the cycloheptatriene (99) into the requisite 10 c-electron system (100) was then accomplished by dehydrogenation. ... 

Another tetrakisdehydro[14]annuleno[14]annulene (LXI) is of some interest because two different types of bisdehydro[14]annulene are fused together, the B ring being of the sort which in either Kckulc form contains a triple bond and an allenic system [272]. 

No mention has been made in this discussion of annulenoannulenes with smaller than ten-membered rings. Some examples of these compounds, such as [8]annuleno[8]annulene, or octalene, will be mentioned in the following chapter. 

An example of an annulenoannulene with one bond common to both rings is the following tetrakisdehydro[14]annuleno[14]annulene [270] ... 

Agranat I, Hess BA Jr, Schaad U (1980) Aromaticity of Non—Alternant Annuleno-annulenes and of Corannulenes. Pure Appl Chem 52 1399... 

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