Synthesis of a novel bis-triquinane: a photochemical rearrangement in cyclohexadienone moiety resulting in aromatisation

The first synthesis of the bird-shaped bis-triquinane 7, possessing a fascinating molecular architecture from readily available materials 2,6-dimethyl phenol and cyclopentadiene has been reported. Pentasubstituted phenols 9 and 10 were isolated during attempted photochemical oxa di-π methane rearrangement of acetic acid 3-(9-acetoxy-7,9-dimethyl-8-oxo-3a,4,7,7a-tetrahydro-1H-4,7-ethano-inden-5-ylmethyl)-1,5-dimethyl-6-oxo-cyclohexa-2,4-dienylester 4, a fused bicyclic system connected with a 2,4-cyclohexadienone unit. A probable mechanism is proposed for aromatisation.