Designing a reusable chiral SPE electrode with Mg nanoparticles on graphene oxide for efficient enantioselective Grignard carboxylation of (1-bromoethyl)benzenes in a deep eutectic solvent

Abstract

Researchers have developed a novel electrode for the enantioselective electro-organic Grignard carboxylation of (1-bromoethyl)benzenes 1(a–l) with carbon dioxide (CO₂) 3(a). This study focuses on using Mg nanoparticle-catalyzed graphene oxide modified with Prl-tacd@Mg, with a surface area of 95.3 [m² g⁻¹] which, when combined with a choline chloride acetamide (ChCl/Ac) deep eutectic solvent, significantly enhances electrochemical performance. The goal is to achieve high selectivity and efficiency in the carboxylation process, contributing to sustainable chemical transformations. This innovative approach allows for the electro-organic synthesis of (R)-2-phenylpropanoic acid derivatives at a current of 15 mA for 30 min at room temperature, achieving yields between 88% and 96%. The ChCl/Ac system serves as a cost-effective electrolyte and solvent, facilitating an increased reaction rate. The synthesized products were characterized through various analytical techniques, including melting point analysis, 1HNMR spectroscopy, and CHN composition analysis. The electrode's performance was thoroughly evaluated using techniques such as X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, cyclic voltammetry (CV), and Fourier-transform infrared spectroscopy (FT-IR). Its affordability and environmentally friendly characteristics highlight its potential for advancing sustainable electro-organic synthesis processes.