Supramolecular Electrosynthesis: An Approach to Sustainable Redoxneutral Reactions

Pal, Priyaraj (2025) Supramolecular Electrosynthesis: An Approach to Sustainable Redoxneutral Reactions. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Priyaraj Pal (20MS049)) 20MS049_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

Organic synthesis is integral to industries ranging from pharmaceuticals to materials science, yet its reliance on petroleum-derived solvents and reagents raises significant sustainability concerns. Traditional solvents, often toxic and environmentally hazardous, contribute to over 80% of organic waste, prompting the need for greener alternatives. This work explores supramolecular electrosynthesis as a sustainable approach, leveraging water as a solvent and electrochemistry to minimize waste and avoid stoichiometric reagents. By combining the hydrophobic effect, micellar catalysis, and electrochemical activation, we develop methodologies for C–C bond formation and heterocycle synthesis under mild, aqueous conditions. In Chapter 2, we demonstrate a redox-neutral phenyl-carbonyl coupling mediated by cationic micelles (CTAB) at a graphite cathode. Optimized conditions (pH 1, 20 mA) achieve 27% yield via a radical mechanism, supported by CV studies and TEMPO inhibition. The micelles act as nanoreactors, localizing reactants near the electrode while suppressing side reactions. Chapter 3 introduces a supramolecular electrochemical synthesis of 2-phenyl oxazolines from N-allylbenzamides, avoiding redox steps. Key innovations include: • In situ halogen generation (I₂) for halonium intermediate formation. • Biomimetic amphiphile design (NDCI) to lower the pKa of a catalytic hydroxyl group, enabling N–H abstraction and cyclization. • Coacervate-like assemblies (NDCI/TPGS-750-M) that enhance substrate loading and selectivity, yielding oxazolines up to 80%. This work highlights the potential of supramolecular electrochemistry to replace traditional organic synthesis with water-based, catalyst-free alternatives. By exploiting self-assembled nanostructures and electrode-driven reactivity, we address challenges in sustainability, selectivity, and post-petroleum chemistry. Future directions include mechanistic elucidation, substrate scope expansion, and applications in complex molecule synthesis.

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