This reaction is very similar to that reported by Marks for the alkylation of hexachlorocyclopentadiene with triethyl phosphite to give 1, 2, 3, 4, 5- pentachloroethylcyclopentadiene and probably occurs by a similar mechanism as shown in Scheme III. a This scheme suggests initial attack on halogen to give the anion and [ClP (OC2Hs) a]+. The ion pair will decompose in ethanol to form I1 and triethyl ph~ sphate.~ In ...