An efficient dechlorination method for l,2,3,4-tetrachloro-5,5-dimethoxycyclopentadiene diels-alder adducts: Inverse addition-ethereal birch reduction conditions

Modified Birch reduction conditions for the selective dechlorination of l,2,3,4-tetrachloro-5,5-dimethoxycyclopentadiene Diels-Alder adducts are described. Inverse addition of a suspension of lithium in liquid ammonia to a dilute ethereal solution of the adduct at — 78 °C gives clean dechlorination with no accompanying alkene reduction.