Efficient one-pot synthesis of chlorinated cyclopentenones from hexachlorocyclopentadiene

The interaction of hexachlorocyclopentadiene (CpCl₆) with KOH in MeOH followed by acidic treatment of the reaction mass results in synthetically valuable 2,3,5-trichloro-4,4-dimethoxy- or 2,5-dichloro-3,4,4-trimethoxycyclopent-2-en-1-ones.