Electroreduction of organic compounds part 33 - 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 ca rboxylic acids by galvanostatic electroreduction in the presence of carbon dioxide ("electrocarboxylation"). Dry DMF was used as solvent, zinc or stai nless 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 ac ids, e.g. 22 and 29, occurs in the dibenzofuran and naphthalene series.