Convergent paired electrosynthesis of different types of bis-β-diketone derivatives based on the knoevenagel condensation reaction under green conditions

Abstract

A green convergent paired electrochemical protocol has been developed for the synthesis of some bis-β-diketones via Knoevenagel condensation reaction. In this method, the electrochemical oxidation of primary alcohols to the corresponding aldehydes have taken at anode and the reduction of β-diketones to active methylene compounds has happened in cathode. In next step, the cathodically activated methylene reacts with anodically generated aldehyde. Different types of bis-β-diketones have been synthesized using C1–C5 primary alcohols and different β-diketones. In this work, we proposed a unique convergent paired mechanism for the synthesis of bis-β-diketones based on possible anodic and cathodic reactions. The effective parameters such as, solution pH, current density, electrode material, alcohol concentration and type of cell have also been optimized. This method provides a new strategy for the synthesis of a wide range of products in the mild conditions and in an undivided cell without using the any catalyst and toxic solvent.