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 (=β‐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.