Tailored Catalysis as a Cornerstone for Advancing Green Chemistry: A Call for Sustainable Innovation

Abstract:

This manuscript reviews tailored organocatalysis as a key part of green chemistry. It highlights metal-free, recyclable systems that support sustainable synthesis. Tailored organocatalysts include proline derivatives, thioureas, Cinchona alkaloids, and N-heterocyclic carbenes (NHCs). They achieve high conversion rates of over 95% in aldol additions, Michael additions, and C-C couplings under mild conditions, such as water or deep eutectic solvents (DES). Proline derivatives enable biodegradable aldol reactions with greater than 95% enantiomeric excess (ee). Squaramides allow for high-turnover cascades in DES, which can be recycled without using toxic solvents. Custom catalysts also reach over 95% efficiency in CO2 conversion and biomass upgrades, remaining recyclable for over 10 cycles and outperforming traditional methods with less than 40% atom economy. Atomic economy hits 98% in regioselective Fe/Co/Ni systems and 100% in photocatalytic Cu clusters for C-H activation. This helps minimize byproducts through enamine/iminium and hydrogenbonding activation. Single-atom Pd catalysts ensure a 90% reduction in waste for boration/C-C couplings at room temperature. AuLaMnCuO3 perovskites achieve 95% conversion of ethanol to acetaldehyde at 225°C with stability for 500 hours. Biocatalyst hybrids made from agro-waste reach 99% enantiopurity in water-based esterifications, which supports circular economies. These innovations replace stoichiometric agents, drastically reducing E-factors and enabling scalable pharmaceutical processes that produce over 99% ee products.