ChemInform Abstract: Forfeiture of the Aromaticity of a Bridged (10)Annulene by Benzanellation.

ChemInform Abstract

Starting from the known diester (I) the diacid (IV) is obtained. On heating in PPA (IV) yields the rearranged dione (V) via (VI). The dione (VI) (space group P1) is obtained from (IV) either in PPA at room temp. or in better yield by intramolecular Friedel-Crafts acylation; reduction of dione (VI) via tosylhydrazone/MeLi or, better, via diol leads to the methano(10)annulene (VII) which between 30-120 °C shows no evidence of any isomerization to (VIII).