4, 5, 6, 7-Tetrachloro-3a, 4, 7, 7a-tetrahydro-4, 7-methanoinden-8-one (IV) has been prepared by the hydrolysis of the adduct of cyclopentadiene and 1, 2, 3, 4-tetrachloro-5, 5- diethoxycyclopentadiene. It has been shown to undergo quantitative thermal isomerization to 2, 3, 3a, 7a-tetrachloro-3a, 4, 7, 7a-tetrahydro-4, 7-methanoinden-1-one (XV), whose structure has been established by its degradation to 2, 3-dichloro-bicyclo [2.2. 1] heptane- ...
