Polycyclic rearrangements: novel Lewis acid-catalysed rearrangement of the pentacyclo[5.4.0.02,6.03,10.05,9]undecane framework; X-ray crystal structure of 1,10-dimethylpentacyclo[5.4.0.02,6.03,10.04,8]- undecane-9,11-dione
Abstract
The pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione derivatives (4) and (5) on exposure to boron trifluoridediethyl ether undergo a hitherto unknown rearrangement to the novel pentacyclo[5.4.0.02,6.03,10.04,8]- undecane ring system (7) and (8).