Electrochemical Oxidation of Catechols (=Benzene-1,2-diols) in the Presence of Benzoylacetonitrile: Synthesis of New Derivatives of 5,6-Dihydroxybenzofuran

The electrochemical oxidation of catechol (=benzene-1,2-diol; 1a) and some of its derivatives in H2O/MeCN 1?:?1 containing benzoylacetonitrile (=beta-oxobenzenepropanenitrile; 3) as a nucleophile was studied by cyclic voltammetry and controlled-potential coulometry. The voltammetric data showed that electrochemically generated o-benzoquinones (=cyclohexa-3,5-diene-1,2-diones) from catechol (1a) and 3-methylcatechol (1b) participate in a Michael-addition reaction with 3 to form the corresponding 5,6-dihydroxybenzofuran-3-carbonitrile 8 (Scheme 1). In this work, we report an efficient one-pot method with high atom economy for the synthesis of new substituted 5,6-dihydroxybenzofuran-3-carbonitriles in an undivided cell under ambient conditions.