Electrocarboxylation of Chlorinated Aromatic Compounds
Chorinated benzenes ( 1 , 4 ), biphenyls ( 6 , 9 ), dibenzofurans ( 10 , 15 , 17 , 18 ), 2-chlorodibenzo[1,4]dioxine ( 24 ) and 1-chloronaphthalene ( 26 ) as well as dibenzofuran ( 12 ) and naphthalene ( 27 ) themselves were transformed into carboxylic acids by galvanostatic electroreduction in the presence of carbon dioxide ("electrocarboxylation"). Dry DMF was used as solvent, zinc or stainless steel as cathode and magnesium as a sacrificial anode in an undivided cell. Hydrogenation of aromatic rings was not observed. However, reductive addition of two molecules of carbon dioxide to form dihydrodicarboxylic acids, e.g. 22 and 29 , occurs in the dibenzofuran and naphthalene series.