Deep Eutectic Solvents and Their Applications as Green Solvents

Several examples demonstrate the effectiveness of Deep Eutectic Solvents (DESs) as eco-friendly alternatives to traditional volatile organic compounds (VOCs) in polar organometallic chemistry, as well as in metal- and bio-catalyzed processes. Beyond their environmental benefits, the use of DESs in these areas has revealed new reactivity features with practical significance that merit detailed mechanistic exploration. Specifically: (a) metal-mediated organic transformations can be carried out in DESs, often at room temperature and in air, without being hindered by protonolysis; (b) metal-catalyzed reactions are more efficient and occur under milder conditions in DESs compared to VOCs, with both the catalyst and DES being easily recycled; and (c) biocatalysts tend to show improved stability, selectivity, and performance in DES mixtures compared to aqueous solutions, with a notable and intriguing effect on stereoselectivity.