A green, simple, catalyst-free, and efficient method for electro-organic synthesis of new benzofuran derivatives.

In this work, the electrochemical oxidation of catechols 1a and 1b was studied in the presence of pyrazolidine-3,5-dione ( 3a), as a nucleophile, in a mixture of ethanol and a phosphate buffer solution (0.1 M, pH 7), as a green medium, using the cyclic voltammetry and controlled-potential coulometry techniques. The results obtained indicated that the oxidized forms of these catechols ( 2a and 2b) participated in the Michael addition reactions with pyrazolidine-3,5-dione ( 3a), and converted, via an ECEC mechanism, to their corresponding benzofurans ( 7a and 7b). In this work, some new benzofuran derivatives were synthesized with good yields and high purities using a facile, one-pot, and environmentally friendly electrochemical method in the absence of any chemical catalyst, toxic solvent, and hard conditions. [ABSTRACT FROM AUTHOR]