Cobalt-catalyzed reductive carboxylation on α,β-unsaturated nitriles with carbon dioxide

The reductive carboxylation of α,β-unsaturated carbonyl compounds with carbon dioxide was studied. After the screening of various transition-metal complex catalysts and reducing agents, it was found that the combination of bis(acetylacetonato) cobalt(II) and diethylzinc could effectively afford the corresponding α-carboxylate in high yield from α,β-unsaturated nitriles. The product was obtained after esterification by trimethylsilyldiazomethane. The highly selective carboxylation was observed at the β-position in the present study.