Exploiting the Versatility of Electrosynthesized Amino-bis(methylene phosphonate) Synthons via Coupling: Enriching the Phosphonate Linker “Toolbox” Toward Metal-Phosphonate Coordination Networks

Abstract

The present research explores an innovative methodology for the synthesis of substituted aminomethylene phosphonates as an alternative route to the traditional phospha-Mannich reactions. This approach involves a two-step process, where the first step employs electrooxidation with a direct current (DC) power supply, carbon electrodes, and hydrochloric acid as the electrolyte to dephosphonomethylate amino methylene phosphonates. This step allows for the controlled and precise removal of the phosphonomethyl group, resulting in less substituted aminomethylene phosphonates. In the second step, the enhanced nucleophilicity of the intermediate amino-dimethylenephosphonate is harnessed to perform straightforward alkylation reactions, ultimately yielding substituted analogs. This innovative route offers an alternative means of producing products similar to those obtained through traditional phospha-Mannich reactions, giving access to compounds that were previously challenging to synthesize. The electrooxidation–alkylation method provides researchers with a valuable and efficient tool for the synthesis of substituted aminomethylene phosphonates, expanding the chemical toolbox for the creation of complex phosphonate and metal phosphonate compounds. This research represents a significant advancement in the fields of organophosphorus and metal phosphonate chemistry, providing a more versatile and tailored approach to the synthesis of these important molecules.