THE PURSUIT OF PERCHLOROTRIPHENYLENE

The synthesis of the polycyclic aromatic chlorocarbon perchlorotriphen ylene (1, dodecachlorotriphenylene) from tetrachlorophthalic anhydride is described, and several approaches to the synthesis of 1 via Diels- Alder additions of 2,3,4,5-tetrachlorothiophene 1,1-dioxide and 5,5-di methoxy-1,2,3,4-tetrachlorocyclopentadiene to naphthalene are also rep orted. The X-ray structure of compound 1 shows it to adopt a C-2 confo rmation which is highly distorted from planarity, but the compound is stable under ordinary conditions. Semiempirical and ab initio molecula r orbital calculations indicate that the C-2 conformation is preferred to a D-3 conformation in the gas phase as well, and these calculation s also indicate that compound 1 is highly flexible and can undergo rap id enantiomerization.