Analysis and Supplement with the Mechanism of Electrosynthesizing Benzofurnan Derivatives

Davood Nematollahi et al. have successfully electrosynthesised a series of benzofuran derivatives in the presence of nucleophile agents. Base on their experimental result, we analyzed the electron density of the intermediate during benzofuran derivatives synthesis and reached the same conclusions as that of Davood Nematollahi et al..Therefore, the method of electron density analysis is proven to be correct and expected to have a wide applications. But after we analyzed the electron density of 2-aldehyde-p-quinone(1a) and 3-carboxyl-o-quinone(7a), we have different opinions with theirs. The electron density of C-6 position of the 2-aldehyde-p-quinone lower than the that of C-5 position leads to the final product 6 when electrochemical oxidation of the 2,5-dihydroxybenzaldehyde. For 2,3-dihydroxybenzoic acid case, since the competition between the carboxyl of the C-2 position and the carboxyl of the C-1’ position in the 3-carboxyl-o-quinone and the hydrogen transferred to the carboxyl of the C-1’ position, there will be a rearrangement before the next electrochemical oxidation and the final product 21 will be formed.