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.
Quantum chemical (DFT) calculations on the course of the electroreductive carboxylation of chloroarenes were performed. An explanation for the extraordinary behaviour of 2- chlorodibenzofuran (2) as compared with the corresponding 1-chloro, 3-chloro and 4-chloro derivatives was sought for and was found in the particular reaction coordinate of 2 and in the SOMO spin density distributions of the four isomers. In the same way, the regioselectivity in the formation of dicarboxylic acids from hexachloro- and 1,2,4,5-tetrachlorobenzene was investigated by DFT-MO calculations and was shown to be due to orbital effects besides steric hindrance.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.