An environmentally friendly electrochemical method for synthesis of benzofuranoquinone derivatives.

Electrochemical oxidation of catechols (1a-c) has been studied in the presence of 2-hydroxy-1,4-naphtoquinone (3b) in aqueous solutions, using cyclic voltammetry and controlled-potential coulometry. The results indicated that the electrochemically generated o-benzoquinones (2a-c) participate in Michael addition reaction with 3b to the corresponding benzofuranoquinones (8a-c, 10a-c). The electrochemical synthesis of these compounds has been successfully preformed at a carbon rod electrode with good yields using an environmentally friendly method.

An improved electrochemical method for the synthesis of some benzofuran derivatives.

Electrochemical oxidation of catechol and some 3-substituted catechols (1a--c) has been studied in the presence of 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3) in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols (1a--c) participate in a Michael addition reaction with 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3) with consumption of only two electrons per molecule of (1a--c) to from the corresponding benzoforans (10a--c). The electrochemical synthesis of benzofurans has been successfully performed at a carbon rod electrode and in an undivided cell with high yields and purity.

Electrochemical oxidation of 2,3-dimethylhydroquinone in the presence of 1,3-dicarbonyl compounds.

The electrooxidation of 2,3-dimethylhydroquinone (1) has been studied in the presence of 2-phenyl-1,3-indandione (3a), 3-hydroxy-1H-phenalen-1-one (3b), and 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3c) as CH acid nucleophiles in water/acetonitrile (85/15) solution, using cyclic voltammetry and controlled-potential coulometry. The results indicate that p-benzoquinone, generated by electrochemically driven oxidation of the 2,3-dimethylhydroquinone (1), is scavenged by 3a-c, to give related products (5a, 9b, 8c) via various electrochemical mechanisms. The electrochemical syntheses of 5a, 9b, and 8c have been successfully performed in one-pot in an undivided cell using an environmentally friendly method with high atomic economy.